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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0706.1714 | Pasquale Blasi | Pasquale Blasi (1,2), Elena Amato (1) ((1) INAF/Osservatorio
Astrofisico di Arcetri, (2) INFN, LNGS) | Theory of nonlinear particle acceleration at shocks and self-generation
of the magnetic field | Contribution to the 30th International Cosmic Ray Conference, Merida,
Mexico | null | null | null | astro-ph | null | We present some recent developments in the theory of particle acceleration at
shock fronts in the presence of dynamical reaction of the accelerated particles
and self-generation of magnetic field due to streaming instability. The spectra
of accelerated particles, the velocity, magnetic field and temperature profiles
can be calculated in this approach anywhere in the precursor and in the
downstream region. The implications for the origin of cosmic rays and for the
phenomenology of supernova remnants will be discussed.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 14:56:37 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Blasi",
"Pasquale",
""
],
[
"Amato",
"Elena",
""
]
] |
0706.1715 | Diego Harari | Diego Harari (for the Pierre Auger Collaboration) | Search for correlation of UHECRs and BL Lacs in Pierre Auger Observatory
data | Contribution to the 30th International Cosmic Ray Conference, Merida,
Mexico, July 2007 | null | null | null | astro-ph | null | Several analyses of the data collected by other experiments have found an
excess of cosmic rays in correlation with subclasses of BL Lacs. Data from the
Pierre Auger Observatory do not support previously reported excesses. The
number of events correlated with BL Lac positions is compatible with that
expected for an isotropic flux.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 14:56:43 GMT"
}
] | 2019-08-13T00:00:00 | [
[
"Harari",
"Diego",
"",
"for the Pierre Auger Collaboration"
]
] |
0706.1716 | Hassane. Alla | Lat\'efa Ghomri (GIPSA-lab), Hassane Alla (GIPSA-lab) | Modeling and analysis using hybrid Petri nets | null | Nonlinear Analysis: Hybrid Systems Volume 1, Issue 2 (01/06/2007)
Pages 141-153 | null | null | cs.IT math.IT | null | This paper is devoted to the use of hybrid Petri nets (PNs) for modeling and
control of hybrid dynamic systems (HDS). Modeling, analysis and control of HDS
attract ever more of researchers' attention and several works have been devoted
to these topics. We consider in this paper the extensions of the PN formalism
(initially conceived for modeling and analysis of discrete event systems) in
the direction of hybrid modeling. We present, first, the continuous PN models.
These models are obtained from discrete PNs by the fluidification of the
markings. They constitute the first steps in the extension of PNs toward hybrid
modeling. Then, we present two hybrid PN models, which differ in the class of
HDS they can deal with. The first one is used for deterministic HDS modeling,
whereas the second one can deal with HDS with nondeterministic behavior.
Keywords: Hybrid dynamic systems; D-elementary hybrid Petri nets; Hybrid
automata; Controller synthesis
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 14:58:17 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Ghomri",
"Latéfa",
"",
"GIPSA-lab"
],
[
"Alla",
"Hassane",
"",
"GIPSA-lab"
]
] |
0706.1717 | Germain Rousseaux | Germain Rousseaux (INLN) | Comment on the paper by Rovelli & al. about the compatibility of various
"gauge conditions" | null | null | null | null | physics.class-ph | null | The compatibility "demonstrated" by Rovelli & al. between various "gauge
conditions" both in Classical Electromagnetism and General Relativity can be
better understood if one distinguishes "gauge conditions" of the solution type
and "gauge conditions" of the constraint type.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 14:59:59 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Rousseaux",
"Germain",
"",
"INLN"
]
] |
0706.1718 | Remi Soummer | R\'emi Soummer and Andr\'e Ferrari | The Strehl Ratio in Adaptive Optics Images: Statistics and Estimation | 8 pages, 5 figures | null | 10.1086/519080 | null | astro-ph | null | Statistical properties of the intensity in adaptive optics images are usually
modeled with a Rician distribution. We study the central point of the image,
where this model is inappropriate for high to very high correction levels. The
central point is an important problem because it gives the Strehl ratio
distribution. We show that the central point distribution can be modeled using
a non-central Gamma distribution.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:03:49 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Soummer",
"Rémi",
""
],
[
"Ferrari",
"André",
""
]
] |
0706.1719 | Michael Prouza | Michael Prouza (for the Pierre Auger Collaboration) | Systematic study of atmosphere-induced influences and uncertainties on
shower reconstruction at the Pierre Auger Observatory | Contribution to the 30th International Cosmic Ray Conference, Merida
Mexico, July 2007; 4 pages, 4 figures | null | null | null | astro-ph | null | A wide range of atmospheric monitoring instruments is employed at the Pierre
Auger Observatory: two laser facilities, elastic lidar stations, aerosol phase
function monitors, a horizontal attenuation monitor, star monitors, weather
stations, and balloon soundings. We describe the impact of analyzed atmospheric
data on the accuracy of shower reconstructions, and in particular study the
effect of the data on the shower energy and the depth of shower maximum (Xmax).
These effects have been studied using the subset of golden hybrid events -
events observed with high quality in the fluorescence and surface detector -
used in the calibration of the surface detector energy spectrum.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:05:28 GMT"
}
] | 2019-08-13T00:00:00 | [
[
"Prouza",
"Michael",
"",
"for the Pierre Auger Collaboration"
]
] |
0706.1720 | Jonas Lindstr{\o}m Jensen | Jonas Lindstr{\o}m Jensen | Correction of paper published in J. Combinatorial Theory 21, 1976: On
the Existence of Hadamard Matrices | 3 pages | null | null | null | math.CO | null | In the paper On the Existence of Hadamard Matrices in J. Combinatorial Theory
21, 1976, it is shown that for a natural number q > 3, we can construct an
Hadamard Matrix of order 2^s q for s \geq t where t = [2 log_2(q-3)]. I will
show that this bound is not a consequence of the proof given in the paper and
explain the error in the argumentation.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:05:59 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Jensen",
"Jonas Lindstrøm",
""
]
] |
0706.1721 | Frank Reifler | Frank Reifler and Randall Morris | Geometric Origin of Physical Constants in a Kaluza-Klein Tetrad Model | null | Found.Phys.Lett.19:657-673,2006 | 10.1007/s10702-006-1056-8 | null | gr-qc astro-ph math-ph math.MP | null | An important feature of Kaluza-Klein theories is their ability to relate
fundamental physical constants to the radii of higher dimensions. In previous
Kaluza-Klein theory, which unifies the electromagnetic field with gravity as
dimensionless components of a Kaluza-Klein metric, i) all fields have the same
physical dimensions, ii) the Lagrangian has no explicit dependence on any
physical constants except mass, and hence iii) all physical constants in the
field equations except for mass originate from geometry. While it seems natural
in Kaluza-Klein theory to add fermion fields by defining higher dimensional
bispinor fields on the Kaluza-Klein manifold, these Kaluza-Klein theories do
not satisfy conditions (i), (ii), and (iii). In this paper, we show how
conditions (i), (ii), and (iii) can be satisfied by including bispinor fields
in a tetrad formulation of the Kaluza-Klein model, as well as in an equivalent
teleparallel model. This demonstrates an unexpected feature of Dirac's bispinor
equation, since conditions (i), (ii), (iii) imply a special relation among the
terms in the Kaluza-Klein or teleparallel Lagrangian that would not be
satisfied in general.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:06:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Reifler",
"Frank",
""
],
[
"Morris",
"Randall",
""
]
] |
0706.1722 | Pasquale Blasi | Pasquale Blasi (1,2), Elena Amato (1) ((1) INAF/Osservatorio
Astrofisico di Arcetri, (2) INFN, LNGS) | A kinetic approach to non resonant modes and growth rates of streaming
instability: consequences for shock acceleration | Paper contribution to the 30th International Cosmic Ray Conference,
July 2007, Merida, Mexico | null | null | null | astro-ph | null | We show here that a purely kinetic approach to the excitation of waves by
cosmic rays in the vicinity of a shock front leads to predict the appearance of
a non-alfvenic fastly growing mode which is the same that was found by Bell
(2004) by treating the plasma in the MHD approximation. The kinetic approach we
present is more powerful in that it allows us to investigate different models
for the compensation of the cosmic ray current in the background upstream
plasma.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:09:06 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Blasi",
"Pasquale",
""
],
[
"Amato",
"Elena",
""
]
] |
0706.1723 | Markus Fendrich | Markus Fendrich, Joachim Krug | Ehrlich-Schwoebel Effect for Organic Molecules: Direct Calculation of
the Step Edge Barrier using Empirical Potentials | 4 pages, 3 figures | null | 10.1103/PhysRevB.76.121302 | null | cond-mat.other | null | The step edge barrier of a prototypical organic semiconductor molecule,
3,4,9,10-perylene-tetracaboxylic-dianhydride (PTCDA) has been analysed by means
of calculations based on emperical potentials. The minimum energy path (MEP)
has been calculated for a single molecule on a substrate of three molecular
layers between equivalent minimum energy positions within two neighboring unit
cells. To determine the step edge barrier, we have calculated the MEP over a
step to a fourth layer of molecules. We found energy barriers of E_D= 80 meV
for in-layer diffusion and E_S = 750 meV for step crossing, indicating a strong
Ehrlich-Schwoebel effect for PTCDA.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:14:14 GMT"
},
{
"version": "v2",
"created": "Wed, 13 Jun 2007 07:27:52 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Fendrich",
"Markus",
""
],
[
"Krug",
"Joachim",
""
]
] |
0706.1724 | Jennifer Hatchell | J. Hatchell, G. A. Fuller, J. S. Richer | Star formation in Perseus: III. Outflows | 26 pages, 21 figures. Version with full colour figures from
http://www.astro.ex.ac.uk/people/hatchell/RecentPapers/hatchell07_outflows.pdf | null | 10.1051/0004-6361:20066467 | null | astro-ph | null | We present a search for outflows towards 51 submillimetre cores in Perseus.
With consistently derived outflow properties from a large homogeneous dataset
within one molecular cloud we can investigate further the mass dependence and
time evolution of protostellar mass loss. Of the 51 cores, 37 show broad
linewings indicative of molecular outflows. In 13 cases, the linewings could be
due to confusion with neighbouring flows but 9 of those sources also have
near-infrared detections confirming their protostellar nature. The total
fraction of protostars in our sample is 65%. All but four outflow detections
are confirmed as protostellar by Spitzer IR detections and only one Spitzer
source has no outflow, showing that outflow maps at this sensitivity are
equally good at identifying protostars as Spitzer. Outflow momentum flux
correlates both with source luminosity and with core mass but there is
considerable scatter even within this one cloud despite the homogeneous
dataset. We fail to confirm the result of Bontemps et al. (1996) that Class I
sources show lower momentum fluxes on average than Class 0 sources, with a KS
test showing a significant probability that the momentum fluxes for both Class
0s and Class Is are drawn from the same distribution. We find that outflow
power may not show a simple decline between the Class 0 to Class I stages. Our
sample includes low momentum flux, low-luminosity Class 0 sources, possibly at
a very early evolutionary stage. If the only mass loss from the core were due
to outflows, cores would last for 10^5-10^8 years, longer than current
estimates of 1.5-4 x 10^5 years for the mean lifetime for the embedded phase.
Additional mechanisms for removing mass from protostellar cores may be
necessary.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 16:09:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hatchell",
"J.",
""
],
[
"Fuller",
"G. A.",
""
],
[
"Richer",
"J. S.",
""
]
] |
0706.1725 | Assaf Naor | Dimitris Achlioptas and Assaf Naor | The two possible values of the chromatic number of a random graph | 17 pages, published version | Ann. of Math. (2) 162 (2005), no. 3, 1335--1351 | null | null | math.PR | null | Given d \in (0,infty) let k_d be the smallest integer k such that d < 2k\log
k. We prove that the chromatic number of a random graph G(n,d/n) is either k_d
or k_d+1 almost surely.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:24:48 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Achlioptas",
"Dimitris",
""
],
[
"Naor",
"Assaf",
""
]
] |
0706.1726 | Christine T. H. Davies | E. Follana, C. T. H. Davies, G. P. Lepage, J. Shigemitsu | High Precision determination of the pi, K, D and D_s decay constants
from lattice QCD | 4 pages, 2 figures. Published version - changes from original include
a more extensive discussion of errors and an error budget table covering more
quantities. There are very small changes in some of the values reported | Phys.Rev.Lett.100:062002,2008 | 10.1103/PhysRevLett.100.062002 | null | hep-lat hep-ph | null | We determine $D$ and $D_s$ decay constants from lattice QCD with 2% errors, 4
times better than experiment and previous theory: $f_{D_s}$ = 241(3) MeV, $f_D$
= 207(4) MeV and $f_{D_s}/f_D$ = 1.164(11).
We also obtain $f_K/f_{\pi}$ = 1.189(7) and $(f_{D_s}/f_D)/(f_K/f_{\pi})$ =
0.979(11). Combining with experiment gives $V_{us}$=0.2262(14) and
$V_{cs}/V_{cd}$ of 4.43(41). We use a highly improved quark discretization on
MILC gluon fields that include realistic sea quarks fixing the $u/d, s$ and $c$
masses from the $\pi$, $K$, and $\eta_c$ meson masses. This allows a stringent
test against experiment for $D$ and $D_s$ masses for the first time (to within
7 MeV).
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:29:21 GMT"
},
{
"version": "v2",
"created": "Fri, 28 Mar 2008 13:39:24 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Follana",
"E.",
""
],
[
"Davies",
"C. T. H.",
""
],
[
"Lepage",
"G. P.",
""
],
[
"Shigemitsu",
"J.",
""
]
] |
0706.1727 | Michael Maziashvili | Michael Maziashvili | Comment on "Elementary Kaluza-Klein towers revisited" | 3 pages | null | null | null | hep-th gr-qc | null | Recently the spectrum of KK modes in the framework of one flat
extra-dimensional scenario was revisited in the paper Phys. Rev. D74 (2006)
124013, (hep-th/0607246) on the basis of self-adjoint extension of the quantum
mechanical operator determining the KK masses. In this Letter we note that the
range of allowed boundary conditions on the KK modes is overestimated in above
mentioned paper and give all allowed possibilities.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:29:27 GMT"
},
{
"version": "v2",
"created": "Fri, 21 Dec 2007 17:22:57 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Maziashvili",
"Michael",
""
]
] |
0706.1728 | Jerome Rocheteau | J\'er\^ome Rocheteau (PPS) | Lambda Mu Calculus and Duality: Call-by-Name and Call-by-Value | null | Term Rewriting and Applications (19/04/2005) 204-218 | null | null | math.LO | null | Under the extension of Curry-Howard's correspondence to classical logic,
Gentzen's NK and LK systems can be seen as syntax-directed systems of simple
types respectively for Parigot's Lambda Mu Calculus and Curien-Herbelin's
Lambda Bar Mu Mu Tidle Calculus. We aim at showing their computational
equivalence. We define translations between these calculi. We prove simulation
theorems for an undirected evaluation as well as for call-by-name and
call-by-value evaluations.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:29:34 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Rocheteau",
"Jérôme",
"",
"PPS"
]
] |
0706.1729 | Bruno Machet | Quentin Duret (LPTHE), Bruno Machet (LPTHE) | Mixing angles of quarks and leptons as an outcome of SU(2) horizontal
symmetries | While calculations are unchanged w.r.t. arXiv:0705.1237, the
horizontal symmetries controlling the mixing angles have been uncovered,
motivating a change of title and a new entry in the arXiv. A new point of
view about which angles are measured has also been adopted | null | null | null | hep-ph | null | We show that all mixing angles are determined, within experimental
uncertainty, by a product of SU(2) horizontal symmetries intimately linked to
the algebra of weak neutral currents. This concerns: on one hand, the three
quark mixing angles; on the other hand, a neutrino-like pattern in which
theta_{23} is maximal and tan (2 theta_{12}) = 2. The latter turns out to
exactly satisfy the ``quark-lepton complementarity condition'' theta_c +
theta_{12} = pi/4. Moreover, among all solutions, two values for the third
neutrino mixing angle arise, which satisfy the bound sin^2(theta_{13}) \leq
0.1: theta_{13} = +/- 5.7 10^{-3} and theta_{13} = +/- 0.2717.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:30:46 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Duret",
"Quentin",
"",
"LPTHE"
],
[
"Machet",
"Bruno",
"",
"LPTHE"
]
] |
0706.1730 | Stephane Vento | St\'ephane Vento (LAMA) | Global well-posedness for dissipative Korteweg-de Vries equations | null | null | null | null | math.AP | null | This paper is devoted to the well-posedness for dissipative KdV equations
$u_t+u_{xxx}+|D_x|^{2\alpha}u+uu_x=0$, $0<\alpha\leq 1$. An optimal bilinear
estimate is obtained in Bourgain's type spaces, which provides global
well-posedness in $H^s(\R)$, $s>-3/4$ for $\alpha\leq1/2$ and
$s>-3/(5-2\alpha)$ for $\alpha>1/2$.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:31:22 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Vento",
"Stéphane",
"",
"LAMA"
]
] |
0706.1731 | Carrie Trundle Dr | C.Trundle (1), P.L. Dufton (1), I. Hunter (1 and 2), C.J. Evans (3),
D.J. Lennon (2), S.J Smartt (1) and R.S.I. Ryans (1) ((1)Astronomy Research
Centre, The Queen's University of Belfast, Belfast, UK (2)The Isaac Newton
Group of Telescopes, Canary Islands, Spain (3)UK Astronomy Technology Centre,
Royal Observatory, Edinburgh, UK) | The VLT-FLAMES survey of massive stars: Evolution of surface N
abundances and effective temperature scales in the Galaxy and Magellanic
Clouds | Paper accepted by A&A on 6/6/2007. 20 pages, 6 figures, 10 tables,
plus online data. Part of a series of papers on The VLT-FLAMES survey of
massive star | null | 10.1051/0004-6361:20077838 | null | astro-ph | null | We present an analysis of high resolution VLT-FLAMES spectra of 61 B-type
stars with relatively narrow-lined spectra located in 4 fields centered on the
Milky Way clusters; NGC3293 & NGC4755 and the Large and Small Magellanic cloud
clusters; NGC2004 and NGC330. For each object a quantitative analysis was
carried out using the non-LTE model atmosphere code TLUSTY; resulting in the
determination of their atmospheric parameters and photospheric abundances of
the dominant metal species (C, N, O, Mg, Si, Fe). The results are discussed in
relation to our earlier work on 3 younger clusters in these galaxies; NGC6611,
N11 and NGC346 paying particular attention to the nitrogen abundances which are
an important probe of the role of rotation in the evolution of stars. This work
along with that of the younger clusters provides a consistent dataset of
abundances and atmospheric parameters for over 100 B-type stars in the three
galaxies. We provide effective temperature scales for B-type dwarfs in all
three galaxies and for giants and supergiants in the SMC and LMC. In each
galaxy a dependence on luminosity is found between the three classes with the
unevolved dwarf objects having significantly higher effective temperatures. A
metallicity dependence is present between the SMC and Galactic dwarf objects,
and whilst the LMC stars are only slightly cooler than the SMC stars, they are
significantly hotter than their Galactic counterparts.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:31:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Trundle",
"C.",
"",
"1 and 2"
],
[
"Dufton",
"P. L.",
"",
"1 and 2"
],
[
"Hunter",
"I.",
"",
"1 and 2"
],
[
"Evans",
"C. J.",
""
],
[
"Lennon",
"D. J.",
""
],
[
"Smartt",
"S. J",
""
],
[
"Ryans",
"R. S. I.",
""
]
] |
0706.1732 | Andre de Gouvea | Andre de Gouvea | GeV Seesaw, Accidentally Small Neutrino Masses, and Higgs Decays to
Neutrinos | 11 pages, revtex, 3 eps figures, references and constraint added,
conclusions unchanged | null | null | NUHEP-TH/07-06 | hep-ph | null | If the Standard Model particle content is extended by gauge singlet fermions
(right-handed neutrinos), active neutrinos generically acquire (Majorana)
masses, in agreement with our current understanding of the lepton sector. If
the right-handed neutrino masses are of the same order as the electroweak
symmetry breaking scale, it is usually expected that these will not mediate any
experimentally observable effects. Here, I explore the fact that this is not
necessarily the case. If neutrino masses are "accidentally small",
active-sterile mixing angles can, according to current experimental bounds, be
as large as several percent. If this is the case, I argue that the dominant
decay mode of light (M_H less than 130 GeV) Higgs bosons could be into an
active and a sterile neutrino. The sterile neutrino decays promptly into a
charge lepton and an on- or off-shell W-boson, so that the dominant Higgs boson
decay mode is H to leptons + jets + missing transverse energy.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:37:05 GMT"
},
{
"version": "v2",
"created": "Wed, 11 Jul 2007 15:58:27 GMT"
}
] | 2007-07-11T00:00:00 | [
[
"de Gouvea",
"Andre",
""
]
] |
0706.1733 | Akinobu Yamaguchi | A. Yamaguchi, T. Ono, Y. Suzuki, S. Yuasa, and H. Miyajima | Magnetic fingerprint in a ferromagnetic wire: Spin torque diode effect
and induction of the DC voltage spectrum inherent in the wire under
application for RF current | 18 pages, 4 figures | null | null | null | cond-mat.mtrl-sci cond-mat.mes-hall | null | We report the rectifying effect of a constant-wave radio frequency (RF)
current by a magnetic domain wall (DW) on a single-layered ferromagnetic wire.
A direct-current (DC) voltage is generated by the spin torque diode effect,
which is a consequence of magnetoresistance oscillation due to the resonant
spin wave excitation induced by the spin-polarized RF current. The DC voltage
spectrum strongly depends on the internal spin structure in the DW, which
corresponds to the magnetic fingerprint of the spin structure in the
ferromagnetic wire.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:41:59 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Yamaguchi",
"A.",
""
],
[
"Ono",
"T.",
""
],
[
"Suzuki",
"Y.",
""
],
[
"Yuasa",
"S.",
""
],
[
"Miyajima",
"H.",
""
]
] |
0706.1734 | Julian Oberdisse | Sylvain Desert (LLB), Vincent Thevenot (LLB), Julian Oberdisse (LCVN),
Annie Brulet (LLB) | The new very small angle neutron scattering spectrometer at Laboratoire
Leon Brillouin | null | J. Appl. Cryst. 40 (01/01/2007) s471-477 | 10.1107/S0021889806055257 | null | cond-mat.soft physics.ins-det | null | The design and characteristics of the new very small angle neutron scattering
spectrometer under construction at the Laboratoire Leon Brillouin is described.
Its goal is to extend the range of scattering vectors magnitudes towards
2x10{-4} /A. The unique feature of this new spectrometer is a high resolution
two dimensional image plate detector sensitive to neutrons. The wavelength
selection is achieved by a double reflection supermirror monochromator and the
collimator uses a novel multibeam design.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:44:56 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Desert",
"Sylvain",
"",
"LLB"
],
[
"Thevenot",
"Vincent",
"",
"LLB"
],
[
"Oberdisse",
"Julian",
"",
"LCVN"
],
[
"Brulet",
"Annie",
"",
"LLB"
]
] |
0706.1735 | Indranil Chakrabarty ic | Indranil Chakrabarty, Prashant, B.S.Choudhury | Self Replication and Signalling | Modified version of quant-ph/0510221, Accepted in International
Journal of Theoretical Physics | IJTP,Volume 46, Number 12, 2007 | 10.1007/s10773-007-9447-6 | null | quant-ph | null | It is known that if one could clone an arbitrary quantum state one could send
signal faster than the speed of light. However it remains interesting to see
that if one can perfectly self replicate an arbitrary quantum state, does it
violate the no signalling principle? Here we see that perfect self replication
would also lead to superluminal signalling.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:47:44 GMT"
},
{
"version": "v2",
"created": "Thu, 14 Jun 2007 16:16:41 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Chakrabarty",
"Indranil",
""
],
[
"Prashant",
"",
""
],
[
"Choudhury",
"B. S.",
""
]
] |
0706.1736 | Neil Smith | Neil Smith | Gilbert and Landau-Lifshitz damping in the presense of spin-torque | 4 pages, no figures. Not presently intended for journal publication | null | null | null | cond-mat.other | null | A recent article by Stiles et al. (cond-mat/0702020) argued in favor of the
Landau-Lifshitz damping term in the micromagnetic equations of motion over that
of the more commonly accepted Gilbert damping form. Much of their argument
revolved around spin-torque driven domain wall motion in narrow magnetic wires,
since the presence of spin-torques can more acutely draw a distinction between
the two forms of damping. In this article, the author uses simple arguments and
examples to offer an alternative point of view favoring Gilbert.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:48:17 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Smith",
"Neil",
""
]
] |
0706.1737 | Gerold Kiesslich | G. Kiesslich, E. Schoell, T. Brandes, F. Hohls, R. J. Haug | Noise enhancement due to quantum coherence in coupled quantum dots | 4 pages, 3 figures, corrected version (Figs.2 and 3) | Phys. Rev. Lett. 99, 206602 (2007) | 10.1103/PhysRevLett.99.206602 | null | cond-mat.mes-hall | null | We show that the intriguing observation of noise enhancement in the charge
transport through two vertically coupled quantum dots can be explained by the
interplay of quantum coherence and strong Coulomb blockade. We demonstrate that
this novel mechanism for super-Poissonian charge transfer is very sensitive to
decoherence caused by electron-phonon scattering as inferred from the measured
temperature dependence.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 15:54:29 GMT"
},
{
"version": "v2",
"created": "Wed, 13 Jun 2007 13:00:05 GMT"
},
{
"version": "v3",
"created": "Wed, 20 Jun 2007 17:03:59 GMT"
}
] | 2007-11-18T00:00:00 | [
[
"Kiesslich",
"G.",
""
],
[
"Schoell",
"E.",
""
],
[
"Brandes",
"T.",
""
],
[
"Hohls",
"F.",
""
],
[
"Haug",
"R. J.",
""
]
] |
0706.1738 | Guo-Niu Han | Guo-Niu Han, Guoce Xin | Permutations with Extremal number of Fixed Points | minor change about corollary 3 | null | null | null | math.CO | null | We extend Stanley's work on alternating permutations with extremal number of
fixed points in two directions: first, alternating permutations are replaced by
permutations with a prescribed descent set; second, instead of simply counting
permutations we study their generating polynomials by number of excedances.
Several techniques are used: Desarmenien's desarrangement combinatorics,
Gessel's hook-factorization and the analytical properties of two new
permutation statistics "DEZ" and "lec". Explicit formulas for the maximal case
are derived by using symmetric function tools.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 16:06:58 GMT"
},
{
"version": "v2",
"created": "Fri, 22 Jun 2007 20:09:33 GMT"
}
] | 2007-06-22T00:00:00 | [
[
"Han",
"Guo-Niu",
""
],
[
"Xin",
"Guoce",
""
]
] |
0706.1739 | Remi Soummer | R\'emi Soummer, Andr\'e Ferrari, Claude Aime, Laurent Jolissaint | Speckle noise and dynamic range in coronagraphic images | 31 pages, 18 figures | null | 10.1086/520913 | null | astro-ph | null | This paper is concerned with the theoretical properties of high contrast
coronagraphic images in the context of exoplanet searches. We derive and
analyze the statistical properties of the residual starlight in coronagraphic
images, and describe the effect of a coronagraph on the speckle and photon
noise. Current observations with coronagraphic instruments have shown that the
main limitations to high contrast imaging are due to residual quasi-static
speckles. We tackle this problem in this paper, and propose a generalization of
our statistical model to include the description of static, quasi-static and
fast residual atmospheric speckles. The results provide insight into the
effects on the dynamic range of wavefront control, coronagraphy, active speckle
reduction, and differential speckle calibration. The study is focused on
ground-based imaging with extreme adaptive optics, but the approach is general
enough to be applicable to space, with different parameters.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 16:11:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Soummer",
"Rémi",
""
],
[
"Ferrari",
"André",
""
],
[
"Aime",
"Claude",
""
],
[
"Jolissaint",
"Laurent",
""
]
] |
0706.1740 | Carl Johan Casselgren | Armen S. Asratian, Carl Johan Casselgren | On path factors of (3,4)-biregular bigraphs | 7 pages | null | null | null | math.CO | null | A (3,4)-biregular bigraph G is a bipartite graph where all vertices in one
part have degree 3 and all vertices in the other part have degree 4. A path
factor of G is a spanning subgraph whose components are nontrivial paths. We
prove that a simple (3,4)-biregular bigraph always has a path factor such that
the endpoints of each path have degree three. Moreover we suggest a polynomial
algorithm for the construction of such a path factor.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 16:11:17 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Asratian",
"Armen S.",
""
],
[
"Casselgren",
"Carl Johan",
""
]
] |
0706.1741 | Rajdeep Sensarma | Rajdeep Sensarma, William Schneider, Roberto B. Diener and Mohit
Randeria | Breakdown of the Thomas Fermi approximation for polarized Fermi gases | 4 pages 3 figures | null | null | null | cond-mat.supr-con cond-mat.str-el | null | We use Bogoliubov de-Gennes theory to show that the commonly used
Thomas-Fermi approximation (TFA) can fail in describing polarized unitary gases
in anisotropic harmonic traps. We find a magnetized superfluid region inside
the trap, with order parameter oscillations, even though there is no such
stable bulk phase. This leads to magnetization profiles that deviate from
contours of constant potential energy. We determine how this violation scales
with trap anisotropy and number of particles, and show that we are able to
account for important differences between the MIT and Rice experiments.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 16:32:39 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Sensarma",
"Rajdeep",
""
],
[
"Schneider",
"William",
""
],
[
"Diener",
"Roberto B.",
""
],
[
"Randeria",
"Mohit",
""
]
] |
0706.1742 | Misha Katsnelson | I. K. Razumov, Yu. N. Gornostyrev, and M. I. Katsnelson | Intrinsic nanoscale inhomogeneity in ordering systems due to
elastic-mediated interactions | final version, Europhys. Lett., accepted | Europhys. Lett. 80, 66001 (2007) | 10.1209/0295-5075/80/66001 | null | cond-mat.stat-mech cond-mat.mtrl-sci | null | Phase diagram and pattern formation in two-dimensional Ising model with
coupling between order parameter and lattice vibrations is investigated by
Monte-Carlo simulations. It is shown that if the coupling is strong enough (or
phonons are soft enough) a short-range order exists in disordered phase for a
broader temperature interval. Different types of this short-range order
(stripe-like, checkboard-like, etc.) depending on the temperature and model
parameters are investigated. With further increase of the coupling, a
reconstruction of the ground state happens and new ordered phases appear at low
enough temperatures.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 16:34:34 GMT"
},
{
"version": "v2",
"created": "Mon, 17 Sep 2007 12:04:28 GMT"
},
{
"version": "v3",
"created": "Fri, 26 Oct 2007 14:28:29 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Razumov",
"I. K.",
""
],
[
"Gornostyrev",
"Yu. N.",
""
],
[
"Katsnelson",
"M. I.",
""
]
] |
0706.1743 | Reinhold A. Bertlmann | Reinhold A. Bertlmann and Philipp Krammer | Bloch vectors for qudits and geometry of entanglement | 30 pages, 4 figures | null | null | null | quant-ph | null | We present three different matrix bases that can be used to decompose density
matrices of d--dimensional quantum systems, so-called qudits: the generalized
Gell-Mann matrix basis, the polarization operator basis, and the Weyl operator
basis. Such a decomposition can be identified with a vector --the Bloch vector,
i.e. a generalization of the well known qubit case-- and is a convenient
expression for comparison with measurable quantities and for explicit
calculations avoiding the handling of large matrices. We consider the important
case of an isotropic two--qudit state and decompose it according to each basis.
Investigating the geometry of entanglement of special parameterized two--qubit
and two--qutrit states, in particular we calculate the Hilbert--Schmidt measure
of entanglement, we find that the Weyl operator basis is the optimal choice
since it is closely connected to the entanglement of the considered states.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 16:45:41 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Bertlmann",
"Reinhold A.",
""
],
[
"Krammer",
"Philipp",
""
]
] |
0706.1744 | Vladislav V. Kravchenko | Kira V. Khmelnytskaya and Vladislav V. Kravchenko | On a complex differential Riccati equation | null | J. of Phys. A, 2008, v. 41, issue 8, 085205. | 10.1088/1751-8113/41/8/085205 | null | math.AP math.CA math.CV | null | We consider a nonlinear partial differential equation for complex-valued
functions which is related to the two-dimensional stationary Schrodinger
equation and enjoys many properties similar to those of the ordinary
differential Riccati equation as, e.g., the famous Euler theorems, the Picard
theorem and others. Besides these generalizations of the classical
"one-dimensional" results we discuss new features of the considered equation
like, e.g., an analogue of the Cauchy integral theorem.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 16:51:18 GMT"
},
{
"version": "v2",
"created": "Fri, 28 Sep 2007 19:15:08 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Khmelnytskaya",
"Kira V.",
""
],
[
"Kravchenko",
"Vladislav V.",
""
]
] |
0706.1745 | Igor Freire | Igor Leite Freire | Noether Symmetries and Conservations Laws For Non-critical Kohn-Laplace
Equations on Three-Dimensional Heisenberg Group | This article was accept for publication in Algebras, Groups and
Geometries. Unfortunately, it was published without my consent in Hadronic
Journal, vol. 30, 299-314, (2007) | null | null | null | math.AP | null | We show which Lie point symmetries of non-critical semilinear Kohn-Laplace
equations on the Heisenberg group $H^1$ are Noether symmetries and we establish
their respectives conservations laws.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 16:51:55 GMT"
},
{
"version": "v2",
"created": "Wed, 13 Feb 2008 23:09:07 GMT"
}
] | 2008-02-14T00:00:00 | [
[
"Freire",
"Igor Leite",
""
]
] |
0706.1746 | Vitaly Braude | V. Braude and Ya. M. Blanter | Triplet Josephson effect with magnetic feedback | 4 pages, 3 figures | null | 10.1103/PhysRevLett.100.207001 | null | cond-mat.supr-con | null | We study AC Josephson effect in a superconductor-ferromagnet heterostructure
with a variable magnetic configuration. The system supports triplet proximity
correlations whose dynamics is coupled to the magnetic dynamics. This feedback
dramatically modifies the behavior of the junction. The current-phase relation
becomes double-periodic at both very low and high Josephson frequencies
$\omega_J$. At intermediate frequencies, the periodicity in $\omega_J t$ may be
lost.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 16:59:51 GMT"
},
{
"version": "v2",
"created": "Wed, 13 Jun 2007 08:25:10 GMT"
}
] | 2013-05-29T00:00:00 | [
[
"Braude",
"V.",
""
],
[
"Blanter",
"Ya. M.",
""
]
] |
0706.1747 | Elisabetta Paladino | E. Paladino, M. Sassetti, G. Falci, U. Weiss | Characterization of coherent impurity effects in solid state qubits | 4 pages, 5 figures. Replaced with published version, minor changes | Phys. Rev. B 77, 041303(R), 2008 | 10.1103/PhysRevB.77.041303 | null | cond-mat.stat-mech cond-mat.mes-hall | null | We propose a characterisation of the effects of bistable coherent impurities
in solid state qubits. We introduce an effective impurity description in terms
of a tunable spin-boson environment and solve the dynamics for the qubit
coherences. The dominant rate characterizing the asymptotic time limit is
identified and signatures of non-Gaussian behavior of the quantum impurity at
intermediate times are pointed out. An alternative perspective considering the
qubit as a measurement device for the spin-boson impurity is proposed.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 17:07:01 GMT"
},
{
"version": "v2",
"created": "Mon, 28 Jan 2008 15:19:16 GMT"
}
] | 2008-01-28T00:00:00 | [
[
"Paladino",
"E.",
""
],
[
"Sassetti",
"M.",
""
],
[
"Falci",
"G.",
""
],
[
"Weiss",
"U.",
""
]
] |
0706.1748 | George Bass Ph.D. | George E. Bass | Crystal Irradiation Stimulation of Enzyme Reactivity: An Explanation | 41 pages, 4 figures, 9 tables | null | null | null | q-bio.SC q-bio.BM | null | In 1968, Sorin Comorosan first reported a phenomenon wherein irradiation of
the substrate of an enzyme reaction, in the crystalline state, for a specific
number of seconds could lead to an enhanced aqueous solution reaction rate for
the enzyme(up to 30%). Dependence on crystal irradiation time was found to be
oscillatory with a fixed period. The basis for this unusual phenomenon has
remained a mystery. Previously unreported experimental results are presented
which demonstrate, for the LDH / pyruvate reaction, that the identity of the
crystalline material irradiated is, largely, inconsequential. It is proposed
here that the irradiation procedure drives oscillatory reactions involving
atmospheric gases adsorbed on the crystals and that these photoproducts, or
related dark-reaction species, when dissolved, function as enzyme cofactors.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 17:22:29 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Bass",
"George E.",
""
]
] |
0706.1749 | Silvia Mollerach | Silvia Mollerach (for the Pierre Auger Collaboration) | Studies of clustering in the arrival directions of cosmic rays detected
at the Pierre Auger Observatory above 10 EeV | Contribution to the 30th International Cosmic Ray Conference, Merida,
Mexico, July 2007 | null | null | null | astro-ph | null | If clustering of the arrival directions of ultra high energy cosmic rays is
discovered, this would provide important information about their origin,
composition, and the galactic and extragalactic magnetic fields. We present
here the analysis of the autocorrelation function of the data from the Pierre
Auger Observatory as a function of the angular scale and the energy threshold.
We compare our results with the signals found by previous experiments.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 17:19:55 GMT"
}
] | 2019-08-13T00:00:00 | [
[
"Mollerach",
"Silvia",
"",
"for the Pierre Auger Collaboration"
]
] |
0706.1750 | Alexander Kitaev | N. Joshi, A. V. Kitaev, and P. A. Treharne | On the Linearization of the Painleve' III-VI Equations and Reductions of
the Three-Wave Resonant System | Typos are corrected, journal and DOI references are added | J. Math. Phys. 48, 103512 (2007) (42 pages) | 10.1063/1.2794560 | null | math.CA | null | We extend similarity reductions of the coupled (2+1)-dimensional three-wave
resonant interaction system to its Lax pair. Thus we obtain new 3x3 matrix
Fuchs--Garnier pairs for the third and fifth Painleve' equations, together with
the previously known Fuchs--Garnier pair for the fourth and sixth Painleve'
equations. These Fuchs--Garnier pairs have an important feature: they are
linear with respect to the spectral parameter. Therefore we can apply the
Laplace transform to study these pairs. In this way we found reductions of all
pairs to the standard 2x2 matrix Fuchs--Garnier pairs obtained by M. Jimbo and
T. Miwa. As an application of the 3x3 matrix pairs, we found an integral
auto-transformation for the standard Fuchs--Garnier pair for the fifth
Painleve' equation. It generates an Okamoto-like B\"acklund transformation for
the fifth Painleve' equation. Another application is an integral transformation
relating two different 2x2 matrix Fuchs--Garnier pairs for the third Painleve'
equation.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 17:36:45 GMT"
},
{
"version": "v2",
"created": "Thu, 13 Sep 2007 18:52:03 GMT"
},
{
"version": "v3",
"created": "Thu, 15 Nov 2007 14:33:33 GMT"
}
] | 2007-11-15T00:00:00 | [
[
"Joshi",
"N.",
""
],
[
"Kitaev",
"A. V.",
""
],
[
"Treharne",
"P. A.",
""
]
] |
0706.1751 | Maximilien Gadouleau | Maximilien Gadouleau and Zhiyuan Yan | MacWilliams Identity for Codes with the Rank Metric | 25 pages, submitted to EURASIP Journal on Wireless Communications | null | null | null | cs.IT math.IT | null | The MacWilliams identity, which relates the weight distribution of a code to
the weight distribution of its dual code, is useful in determining the weight
distribution of codes. In this paper, we derive the MacWilliams identity for
linear codes with the rank metric, and our identity has a different form than
that by Delsarte. Using our MacWilliams identity, we also derive related
identities for rank metric codes. These identities parallel the binomial and
power moment identities derived for codes with the Hamming metric.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 17:38:47 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Jul 2007 17:56:07 GMT"
},
{
"version": "v3",
"created": "Wed, 28 Nov 2007 03:36:59 GMT"
}
] | 2007-11-28T00:00:00 | [
[
"Gadouleau",
"Maximilien",
""
],
[
"Yan",
"Zhiyuan",
""
]
] |
0706.1752 | Alexander Rezounenko V | Alexander V. Rezounenko | Partial Inertial Manifolds for infinite-dimensional dynamical systems:
Example for P.D.E.s with a state-dependent delay | 13 pages | null | null | null | math.DS math.AP | null | We propose a new notion of Partial Inertial Manifold to study the long-time
asymptotic behavior of dissipative differential equations. As shown on an
example, such manifolds may exist in the cases when the classical Inertial
manifold does not exist (or not known to exist).
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 17:41:12 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Rezounenko",
"Alexander V.",
""
]
] |
0706.1753 | Christian Houdre | Christian Houdr\'e, Hua Xu | Concentration of the Spectral Measure for Large Random Matrices with
Stable Entries | 35 pages | null | null | null | math.PR math.ST stat.TH | null | We derive concentration inequalities for functions of the empirical measure
of large random matrices with infinitely divisible entries and, in particular,
stable ones. We also give concentration results for some other functionals of
these random matrices, such as the largest eigenvalue or the largest singular
value.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 18:01:23 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Houdré",
"Christian",
""
],
[
"Xu",
"Hua",
""
]
] |
0706.1754 | Ivan Rankenburg Ph.D. | Ivan C. Rankenburg, Veit Elser | Protein structure prediction by an iterative search method | 20 pages, 7 figures | null | null | null | q-bio.BM | null | We demonstrate a new algorithm for finding protein conformations that
minimize a non-bonded energy function. The new algorithm, called the difference
map, seeks to find an atomic configuration that is simultaneously in two
constraint spaces. The first constraint space is the space of atomic
configurations that have a valid peptide geometry, while the second is the
space of configurations that have a non-bonded energy below a given target.
These two constraint spaces are used to define a deterministic dynamical
system, whose fixed points produce atomic configurations in the intersection of
the two constraint spaces. The rate at which the difference map produces low
energy protein conformations is compared with that of a contemporary search
algorithm, parallel tempering. The results indicate the difference map finds
low energy protein conformations at a significantly higher rate then parallel
tempering.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 18:07:49 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Rankenburg",
"Ivan C.",
""
],
[
"Elser",
"Veit",
""
]
] |
0706.1755 | Kirill Bolshakov | Kirill Bolshakov (1), Elena Reshetova (1) ((1) Saint-Petersburg State
University of Aerospace Instrumentation) | FreeBSD Mandatory Access Control Usage for Implementing Enterprise
Security Policies | 6 pages, 3 figures, submitted to XI International Symposium "Problems
of redundancy in information and control systems" | null | null | null | cs.CR | null | FreeBSD was one of the first widely deployed free operating systems to
provide mandatory access control. It supports a number of classic MAC models.
This tutorial paper addresses exploiting this implementation to enforce typical
enterprise security policies of varying complexities.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 18:11:15 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Bolshakov",
"Kirill",
""
],
[
"Reshetova",
"Elena",
""
]
] |
0706.1756 | Irina Stefanescu | I. Stefanescu (K.U. Leuven, Nipne), A. Gelberg (Koln Univ.), J. Jolie
(Koln Univ.), P. Van Isacker (GANIL), P. Von Brentano (Koln Univ.), Y.X. Luo
(Vanderbilt Univ., LBNL), S.J. Zhu (Vanderbilt Univ., Tsinghua Univ.), J.O.
Rasmussen (LBNL), J.H. Hamilton (Vanderbilt Univ.), A.V. Ramayya (Vanderbilt
Univ.), X.L. Che (Tsinghua Univ.) | IBM-1 description of the fission products $^{108,110,112}$Ru | 22 pages, 8 figures | Nucl.Phys.A789:125-141,2007 | 10.1016/j.nuclphysa.2007.03.007 | GANIL P 07 08 | nucl-th | null | IBM-1} calculations for the fission products $^{108,110,112}$Ru have been
carried out. The even-even isotopes of Ru can be described as transitional
nuclei situated between the U(5) (spherical vibrator) and SO(6)
($\gamma$-unstable rotor) symmetries of the Interacting Boson Model. At first,
a Hamiltonian with only one- and two-body terms has been used. Excitation
energies and $B$(E2) ratios of gamma transitions have been calculated. A
satisfactory agreement has been obtained, with the exception of the odd-even
staggering in the quasi-$\gamma$ bands of $^{110,112}$Ru. The observed pattern
is rather similar to the one for a rigid triaxial rotor. A calculation based on
a Hamiltonian with three-body terms was able to remove this discrepancy. The
relation between the IBM and the triaxial rotor model was also examined.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 18:12:33 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Stefanescu",
"I.",
"",
"K.U. Leuven, Nipne"
],
[
"Gelberg",
"A.",
"",
"Koln Univ."
],
[
"Jolie",
"J.",
"",
"Koln Univ."
],
[
"Van Isacker",
"P.",
"",
"GANIL"
],
[
"Von Brentano",
"P.",
"",
"Koln Univ."
],
[
"Luo",
"Y. X.",
"",
"Vanderbilt Univ., LBNL"
],
[
"Zhu",
"S. J.",
"",
"Vanderbilt Univ., Tsinghua Univ."
],
[
"Rasmussen",
"J. O.",
"",
"LBNL"
],
[
"Hamilton",
"J. H.",
"",
"Vanderbilt Univ."
],
[
"Ramayya",
"A. V.",
"",
"Vanderbilt\n Univ."
],
[
"Che",
"X. L.",
"",
"Tsinghua Univ."
]
] |
0706.1757 | Jan M. L. Martin | Amir Karton, Peter R. Taylor, and Jan M. L. Martin | Basis set convergence of post-CCSD contributions to molecular
atomization energies | (J. Chem. Phys., in press) | Journal of Chemical Physics 127, 064104 (2007) | 10.1063/1.2755751 | null | physics.chem-ph | null | Basis set convergence of correlation effects on molecular atomization
energies beyond the CCSD (coupled cluster with singles and doubles)
approximation has been studied near the one-particle basis set limit.
Quasiperturbative connected triple excitations, (T), converge more rapidly than
$L^{-3}$ (where $L$ is the highest angular momentum represented in the basis
set), while higher-order connected triples, $T_3-(T)$, converge more slowly --
empirically, $\propto L^{-5/2}$. Quasiperturbative connected quadruple
excitations, (Q), converge smoothly as $\propto L^{-3}$ starting with the
cc-pVTZ basis set, while the cc-pVDZ basis set causes overshooting of the
contribution in highly polar systems. Higher-order connected quadruples display
only weak, but somewhat erratic, basis set dependence. Connected quintuple
excitations converge very rapidly with the basis set, to the point where even
an unpolarized double-zeta basis set yields useful numbers. In cases where
fully iterative CCSDTQ5 (coupled cluster up to connected quintuples)
calculations are not an option, CCSDTQ(5) (i.e., coupled cluster up to
connected quadruples plus a quasiperturbative connected quintuples correction)
cannot be relied upon in the presence of significant nondynamical correlation,
whereas CCSDTQ(5)$_\Lambda$ represents a viable alternative. Connected
quadruples corrections to the core-valence contribution are thermochemically
significant in some systems. [...] We conclude that ``$3\sigma\leq 1$ kJ/mol''
thermochemistry is feasible with current technology, but that the more
ambitious goal of $\pm$10 cm$^{-1}$ accuracy is illusory, at least for
atomization energies.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 18:16:43 GMT"
}
] | 2008-08-17T00:00:00 | [
[
"Karton",
"Amir",
""
],
[
"Taylor",
"Peter R.",
""
],
[
"Martin",
"Jan M. L.",
""
]
] |
0706.1758 | Luis Carlos Malacarne | R. S. Mendes, L. C. Malacarne and C. Anteneodo | Statistics of football dynamics | 7 pages | null | 10.1140/epjb/e2007-00177-4 | null | physics.data-an | null | We investigate the dynamics of football matches. Our goal is to characterize
statistically the temporal sequence of ball movements in this collective sport
game, searching for traits of complex behavior. Data were collected over a
variety of matches in South American, European and World championships
throughout 2005 and 2006. We show that the statistics of ball touches presents
power-law tails and can be described by $q$-gamma distributions. To explain
such behavior we propose a model that provides information on the
characteristics of football dynamics. Furthermore, we discuss the statistics of
duration of out-of-play intervals, not directly related to the previous
scenario.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 18:26:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Mendes",
"R. S.",
""
],
[
"Malacarne",
"L. C.",
""
],
[
"Anteneodo",
"C.",
""
]
] |
0706.1759 | Taras Lakoba | T.I. Lakoba and J. Yang | A generalized Petviashvili iteration method for scalar and vector
Hamiltonian equations with arbitrary form of nonlinearity | to appear in J. Comp. Phys.; 35 pages | null | 10.1016/j.jcp.2007.06.009 | null | nlin.PS | null | The Petviashvili's iteration method has been known as a rapidly converging
numerical algorithm for obtaining fundamental solitary wave solutions of
stationary scalar nonlinear wave equations with power-law nonlinearity: \
$-Mu+u^p=0$, where $M$ is a positive definite self-adjoint operator and $p={\rm
const}$. In this paper, we propose a systematic generalization of this method
to both scalar and vector Hamiltonian equations with arbitrary form of
nonlinearity and potential functions. For scalar equations, our generalized
method requires only slightly more computational effort than the original
Petviashvili method.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 18:40:27 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lakoba",
"T. I.",
""
],
[
"Yang",
"J.",
""
]
] |
0706.1760 | Tom Steele | F.A. Chishtie, T. Hanif, D.G.C. McKeon, T.G. Steele | A Unique Determination of the Effective Potential in Terms of
Renormalization Group Functions | latex, 9 pages. v3 has been restructured to incorporate an analysis
of massless scalae QED | Phys.Rev.D77:065007,2008 | 10.1103/PhysRevD.77.065007 | null | hep-ph | null | The perturbative effective potential V in the massless $\lambda\phi^4$ model
with a global O(N) symmetry is uniquely determined to all orders by the
renormalization group functions alone when the Coleman-Weinberg renormalization
condition $\frac{d^4V}{d\phi^4}|_{\phi = \mu} = \lambda$ is used, where $\mu$
represents the renormalization scale. Systematic methods are developed to
express the n-loop effective potential in the Coleman-Weinberg scheme in terms
of the known n-loop minimal subtraction (MS) renormalization-group functions.
Moreover, it also proves possible to sum the leading- and
subsequent-to-leading-logarithm contributions to V. An essential element of
this analysis is a conversion of the renormalization group functions in the
Coleman-Weinberg scheme to the renormalization group functions in the MS
scheme. As an example, the explicit five-loop effective potential is obtained
from the known five-loop MS renormalization group functions and we explicitly
sum the leading logarithm (LL), next-to-leading (NLL), and further
subleading-logarithm contributions to V. Extensions of these results to
massless scalar QED are also presented. Because massless scalar QED has two
couplings, conversion of the RG functions from the MS scheme to the CW scheme
requires the use of multi-scale renormalization group methods.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 18:33:22 GMT"
},
{
"version": "v2",
"created": "Thu, 27 Sep 2007 19:32:10 GMT"
},
{
"version": "v3",
"created": "Wed, 20 Feb 2008 18:11:45 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chishtie",
"F. A.",
""
],
[
"Hanif",
"T.",
""
],
[
"McKeon",
"D. G. C.",
""
],
[
"Steele",
"T. G.",
""
]
] |
0706.1761 | Eric Rowell | Eric C. Rowell (2), Yong Zhang (1), Yong-Shi Wu (1), Mo-Lin Ge (3)
(1.Utah 2.TAMU 3. Nankai) | Extraspecial Two-Groups, Generalized Yang-Baxter Equations and Braiding
Quantum Gates | v1: Latex, 28 pages; v2: comment and references added; v3: Title and
authors changed. Significantly more concise than previous versions, now 21
pages | Quant.Inf.Comput.10:685-702,2010 | null | null | quant-ph hep-th math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper we describe connections among extraspecial 2-groups, unitary
representations of the braid group and multi-qubit braiding quantum gates. We
first construct new representations of extraspecial 2-groups. Extending the
latter by the symmetric group, we construct new unitary braid representations,
which are solutions to generalized Yang-Baxter equations and use them to
realize new braiding quantum gates. These gates generate the GHZ
(Greenberger-Horne-Zeilinger) states, for an arbitrary (particularly an
\emph{odd}) number of qubits, from the product basis. We also discuss the
Yang-Baxterization of the new braid group representations, which describes
unitary evolution of the GHZ states. Our study suggests that through their
connection with braiding gates, extraspecial 2-groups and the GHZ states may
play an important role in quantum error correction and topological quantum
computing.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 19:16:55 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 02:48:20 GMT"
},
{
"version": "v3",
"created": "Mon, 30 Aug 2010 19:13:02 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Rowell",
"Eric C.",
""
],
[
"Zhang",
"Yong",
""
],
[
"Wu",
"Yong-Shi",
""
],
[
"Ge",
"Mo-Lin",
""
]
] |
0706.1762 | Chow-Choong Ngeow | C. Koen (Western Cape), S. Kanbur (SUNY-Oswego), C. Ngeow (UIUC) | The Detailed Forms of the LMC Cepheid PL and PLC Relations | 20 pages, 20 figures, MNRAS accepted | Mon.Not.Roy.Astron.Soc.380:1440-1448,2007 | 10.1111/j.1365-2966.2007.12101.x | null | astro-ph | null | Possible deviations from linearity of the LMC Cepheid PL and PLC relations
are investigated. Two datasets are studied, respectively from the OGLE and
MACHO projects. A nonparametric test, based on linear regression residuals,
suggests that neither PL relation is linear. If colour dependence is allowed
for then the MACHO PL relation is found to deviate more significantly from the
linear, while the OGLE PL relation is consistent with linearity. These finding
are confirmed by fitting "Generalised Additive Models" (nonparametric
regression functions) to the two datasets. Colour dependence is shown to be
nonlinear in both datasets, distinctly so in the case of the MACHO Cepheids. It
is also shown that there is interaction between the period and colour functions
in the MACHO data.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 18:40:58 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Koen",
"C.",
"",
"Western Cape"
],
[
"Kanbur",
"S.",
"",
"SUNY-Oswego"
],
[
"Ngeow",
"C.",
"",
"UIUC"
]
] |
0706.1763 | Nathan Ng | Nathan Ng | A discrete mean value of the derivative of the Riemann zeta function | 41 pages | null | null | null | math.NT | null | In this article we compute a discrete mean value of the derivative of the
Riemann zeta function. This mean value will be important for several
applications concerning the size of $\zeta'(\rho)$ where $\zeta(s)$ is the
Riemann zeta function and $\rho$ is a non-trivial zero of the Riemann zeta
function.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 18:37:23 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Ng",
"Nathan",
""
]
] |
0706.1764 | Richard G. Hennig | R. G. Hennig, T. J. Lenosky, D. R. Trinkle, S. P. Rudin, J. W. Wilkins | Classical potential describes martensitic phase transformations between
the $\alpha$, $\beta$ and $\omega$ titanium phases | 10 pages, 6 figures | null | 10.1103/PhysRevB.78.054121 | null | cond-mat.mtrl-sci | null | A description of the martensitic transformations between the $\alpha$,
$\beta$ and $\omega$ phases of titanium that includes nucleation and growth
requires an accurate classical potential. Optimization of the parameters of a
modified embedded atom potential to a database of density-functional
calculations yields an accurate and transferable potential as verified by
comparison to experimental and density functional data for phonons, surface and
stacking fault energies and energy barriers for homogeneous martensitic
transformations. Molecular dynamics simulations map out the
pressure-temperature phase diagram of titanium. For this potential the
martensitic phase transformation between $\alpha$ and $\beta$ appears at
ambient pressure and 1200 K, between $\alpha$ and $\omega$ at ambient
conditions, between $\beta$ and $\omega$ at 1200 K and pressures above 8 GPa,
and the triple point occurs at 8GPa and 1200 K. Molecular dynamics explorations
of the dynamics of the martensitic $\alpha-\omega$ transformation show a
fast-moving interface with a low interfacial energy of 30 meV/\AA$^2$. The
potential is applicable to the study of defects and phase transformations of
Ti.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 18:37:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hennig",
"R. G.",
""
],
[
"Lenosky",
"T. J.",
""
],
[
"Trinkle",
"D. R.",
""
],
[
"Rudin",
"S. P.",
""
],
[
"Wilkins",
"J. W.",
""
]
] |
0706.1765 | Nathan Ng | Nathan Ng | Extreme values of zeta prime rho | 16 pages | null | 10.1112/jlms/jdn022 | null | math.NT | null | In this article we exhibit small and large values of $\zeta'(\rho)$ by
applying Soundararajan's resonance method. Our results assume the Riemann
hypothesis.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 18:45:18 GMT"
}
] | 2014-02-26T00:00:00 | [
[
"Ng",
"Nathan",
""
]
] |
0706.1766 | Andrzej M. Oles | Louis Felix Feiner and Andrzej M. Oles | Orbital liquid in ferromagnetic manganites: The orbital Hubbard model
for $e_g$ electrons | 25 pages, 9 figures | Phys. Rev. B 71, 144422 (2005) | 10.1103/PhysRevB.71.144422 | null | cond-mat.str-el | null | We have analyzed the symmetry properties and the ground state of an orbital
Hubbard model with two orbital flavors, describing a partly filled
spin-polarized $e_g$ band on a cubic lattice, as in ferromagnetic manganites.
We demonstrate that the off-diagonal hopping responsible for transitions
between $x^2-y^2$ and $3z^2-r^2$ orbitals, and the absence of SU(2) invariance
in orbital space, have important implications. One finds that superexchange
contributes in all orbital ordered states, the Nagaoka theorem does not apply,
and the kinetic energy is much enhanced as compared with the spin case.
Therefore, orbital ordered states are harder to stabilize in the Hartree-Fock
approximation (HFA), and the onset of a uniform ferro-orbital polarization and
antiferro-orbital instability are similar to each other, unlike in spin case.
Next we formulate a cubic (gauge) invariant slave boson approach using the
orbitals with complex coefficients. In the mean-field approximation it leads to
the renormalization of the kinetic energy, and provides a reliable estimate for
the ground state energy of the disordered state. Using this approach one finds
that the HFA fails qualitatively in the regime of large Coulomb repulsion
$U\to\infty$ -- the orbital order is unstable, and instead a strongly
correlated orbital liquid with disordered orbitals is realized at any electron
filling.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 18:47:38 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Feiner",
"Louis Felix",
""
],
[
"Oles",
"Andrzej M.",
""
]
] |
0706.1767 | Massimo Persic | Massimo Persic (INAF & INFN, Trieste), Alessandro De Angelis (Udine U.
& INFN, Udine) | VHE astrophysics: recent developments | 8 pages, invited review, Mem.S.A.It., in press | null | null | null | astro-ph | null | We review the current status, and some open issues, of VHE astrophysics.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 19:54:55 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Persic",
"Massimo",
"",
"INAF & INFN, Trieste"
],
[
"De Angelis",
"Alessandro",
"",
"Udine U.\n & INFN, Udine"
]
] |
0706.1768 | Ofer Aharony | Ofer Aharony, Alex Buchel and Patrick Kerner | The black hole in the throat - thermodynamics of strongly coupled
cascading gauge theories | 45 pages, 13 figures, latex. v2: typo fixed | Phys.Rev.D76:086005,2007 | 10.1103/PhysRevD.76.086005 | UWO-TH-07/10, WIS/07/07-JUNE-DPP, SLAC-PUB-12552 | hep-th | null | We numerically construct black hole solutions corresponding to the
deconfined, chirally symmetric phase of strongly coupled cascading gauge
theories at various temperatures. We compute the free energy as a function of
the temperature, and we show that it becomes positive below some critical
temperature, indicating the possibility of a first order phase transition at
which the theory deconfines and restores the chiral symmetry.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 19:15:55 GMT"
},
{
"version": "v2",
"created": "Tue, 24 Jul 2007 18:53:57 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Aharony",
"Ofer",
""
],
[
"Buchel",
"Alex",
""
],
[
"Kerner",
"Patrick",
""
]
] |
0706.1769 | Boris Pioline | Yann Michel (LPTHE), Boris Pioline (LPTHE, LPTENS) | Higher Derivative Corrections, Dimensional Reduction and Ehlers Duality | 21 pages, uses JHEP3.cls; v3: minor corrections, final version
published in JHEP | JHEP 0709:103,2007 | 10.1088/1126-6708/2007/09/103 | LPTENS-07-24 | hep-th | null | Motivated by applications to black hole physics and duality, we study the
effect of higher derivative corrections on the dimensional reduction of
four-dimensional Einstein, Einstein Liouville and Einstein-Maxwell gravity to
one direction, as appropriate for stationary, spherically symmetric solutions.
We construct a field redefinition scheme such that the one-dimensional
Lagrangian is corrected only by powers of first derivatives of the fields,
eliminating spurious modes and providing a suitable starting point for
quantization. We show that the Ehlers symmetry, broken by the leading $R^2$
corrections in Einstein-Liouville gravity, can be restored by including
contributions of Taub-NUT instantons. Finally, we give a preliminary discussion
of the duality between higher-derivative F-term corrections on the vector and
hypermultiplet branches in N=2 supergravity in four dimensions.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 19:11:12 GMT"
},
{
"version": "v2",
"created": "Thu, 28 Jun 2007 16:24:16 GMT"
},
{
"version": "v3",
"created": "Wed, 3 Oct 2007 14:15:55 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Michel",
"Yann",
"",
"LPTHE"
],
[
"Pioline",
"Boris",
"",
"LPTHE, LPTENS"
]
] |
0706.1770 | Philip Phillips | Philip Phillips and Alexander V. Balatsky | Cracking the Supersolid | Extended version of Science Perspective with more references | Science, vol. 316, 1435 (2007) | null | null | cond-mat.supr-con cond-mat.dis-nn | null | We prepresent an overview of the status of experiment and theory on the
supersolid state of matter.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 19:31:39 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Phillips",
"Philip",
""
],
[
"Balatsky",
"Alexander V.",
""
]
] |
0706.1771 | Eduardo J. Dubuc | Eduardo J. Dubuc | The fundamental progroupoid of a general topos | 19 pages | null | null | null | math.CT math.AT | null | It is well known that the category of covering projections (that is, locally
constant objects) of a locally connected topos is equivalent to the classifying
topos of a strict progroupoid (or, equivalently, a localic prodiscrete
groupoid), the \emph{fundamental progroupoid}, and that this progroupoid
represents first degree cohomology. In this paper we generalize these results
to an arbitrary topos. The fundamental progroupoid is now a localic
progroupoid, and can not be replaced by a localic groupoid. The classifying
topos in not any more a Galois topos. Not all locally constant objects can be
considered as covering projections. The key contribution of this paper is a
novel definition of covering projection for a general topos, which coincides
with the usual definition when the topos is locally connected. The results in
this paper were presented in a talk at the Category Theory Conference,
Vancouver July 2004.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 19:27:27 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Dubuc",
"Eduardo J.",
""
]
] |
0706.1772 | Daniele Malesani | Daniele Malesani (DARK), Emilio Molinari (INAF/Brera), Susanna Vergani
(DIAS and DCU), Stefano Covino (INAF/Brera) (for the REM team) | The GRB afterglow onset observed by REM: fireball Lorentz factor and
afterglow fluence | 4 pages, 1 figure, to appear in New Astronomy Reviews, proceedings of
"070228: The Next Decade of Gamma-Ray Burst Afterglows", Amsterdam, 2007
March 19-23, eds. R.A.M.J. Wijers, L. Kaper, E. van Eerten | null | null | null | astro-ph | null | We report observations of the early light curves of GRB 060418 and GRB
060607A, carried out with the pink robotic telescope REM. A clear peak is
detected for both events, which is interpreted as the onset of the afterglow,
that is the time at which the fireball starts decelerating. This detection
allows to directly measure the initial fireball Lorentz factor, which was found
to be Gamma_0 ~ 400 for both events, fully confirming the ultrarelativistic
nature of gamma-ray burst fireballs. Sampling the light curve before the peak
also allows to compute the bolometric fluence of the afterglow, which is 16% of
the prompt one in the case of GRB 060418.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 19:46:42 GMT"
}
] | 2019-08-14T00:00:00 | [
[
"Malesani",
"Daniele",
"",
"DARK"
],
[
"Molinari",
"Emilio",
"",
"INAF/Brera"
],
[
"Vergani",
"Susanna",
"",
"DIAS and DCU"
],
[
"Covino",
"Stefano",
"",
"INAF/Brera"
]
] |
0706.1773 | Caroline Lambert | Caroline Lambert (Universit\'e de Montr\'eal), Christiane Rousseau
(Universit\'e de Montr\'eal) | The Stokes phenomenon in the confluence of the hypergeometric equation
using Riccati equation | 22 pages v2: revised version | null | null | null | math.CA math.DS | null | In this paper we study the confluence of two regular singular points of the
hypergeometric equation into an irregular one. We study the consequence of the
divergence of solutions at the irregular singular point for the unfolded
system. Our study covers a full neighborhood of the origin in the confluence
parameter space. In particular, we show how the divergence of solutions at the
irregular singular point explains the presence of logarithmic terms in the
solutions at a regular singular point of the unfolded system. For this study,
we consider values of the confluence parameter taken in two sectors covering
the complex plane. In each sector, we study the monodromy of a first integral
of a Riccati system related to the hypergeometric equation. Then, on each
sector, we include the presence of logarithmic terms into a continuous
phenomenon and view a Stokes multiplier related to a 1-summable solution as the
limit of an obstruction that prevents a pair of eigenvectors of the monodromy
operators, one at each singular point, to coincide.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 19:30:40 GMT"
},
{
"version": "v2",
"created": "Thu, 1 Nov 2007 16:50:46 GMT"
}
] | 2007-11-01T00:00:00 | [
[
"Lambert",
"Caroline",
"",
"Université de Montréal"
],
[
"Rousseau",
"Christiane",
"",
"Université de Montréal"
]
] |
0706.1774 | Andre Luis Leite de Lemos | M. Aparicio Alcade, A. L. L. de Lemos and N. F. Svaiter | Functional Methods in the Generalized Dicke Model | null | null | null | null | quant-ph | null | The Dicke model describes an ensemble of N identical two-level atoms (qubits)
coupled to a single mode of a bosonic field. The fermion Dicke model should be
obtained by changing the atomic pseudo-spin operators by a linear combination
of Fermi operators. The generalized fermion Dicke model is defined introducing
different coupling constants between the single mode of the bosonic field and
the reservoir. In the thermodynamic limit, the fermion Dicke model can be
analized using the path integral approach with functional method. The system
exhibits a second order phase transition from normal to superrandiance at some
critical temperature with the presence of a condensate. We evaluate the
critical transition temperature and present the spectrum of the collective
bosonic excitations. There is quantum phantum critical behavior when the
coupling constants satisfy an especific condition. Two particular situations
are analyzed. First, we present the spectrum of the collective bosonic
excitations in the case using the rotating-wave approximation, recovering the
well know results. Second, the case only considering virtual processes. In the
last case, it is possible to have a superradiance phase when only virtual
processes are introduced in the interaction Hamiltonian. Here also appears a
quantum phase transition at some critical coupling, and for larger values for
the critical coupling, the system enter in this superradiant phase with a
Goldstone mode.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 19:31:06 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Alcade",
"M. Aparicio",
""
],
[
"de Lemos",
"A. L. L.",
""
],
[
"Svaiter",
"N. F.",
""
]
] |
0706.1775 | Fabian Schmidt | Fabian Schmidt, Michele Liguori, Scott Dodelson | Galaxy-CMB Cross-Correlation as a Probe of Alternative Models of Gravity | 10 pages, 6 figures, revised version re-submitted to Phys. Rev. D | Phys.Rev.D76:083518,2007 | 10.1103/PhysRevD.76.083518 | null | astro-ph | null | Bekenstein's alternative to general relativity, TeVeS, reduces to Modified
Newtonian Dynamics (MOND) in the galactic limit. On cosmological scales, the
(potential well <-> overdensity) relationship is quite different than in
standard general relativity. Here we investigate the possibility of
cross-correlating galaxies with the cosmic microwave background (CMB) to probe
this relationship. At redshifts of order 2, the sign of the CMB-galaxy
correlation differs in TeVeS from that in general relativity. We show that this
effect is detectable and hence can serve as a powerful discriminator of these
two models of gravity.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 19:51:49 GMT"
},
{
"version": "v2",
"created": "Thu, 30 Aug 2007 22:08:17 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Schmidt",
"Fabian",
""
],
[
"Liguori",
"Michele",
""
],
[
"Dodelson",
"Scott",
""
]
] |
0706.1776 | Roberto D. Pascual-Marqui | Roberto D. Pascual-Marqui | Coherence and phase synchronization: generalization to pairs of
multivariate time series, and removal of zero-lag contributions | Technical report | null | null | null | stat.ME stat.AP | null | Coherence and phase synchronization between time series corresponding to
different spatial locations are usually interpreted as indicators of the
connectivity between locations. In neurophysiology, time series of electric
neuronal activity are essential for studying brain interconnectivity. Such
signals can either be invasively measured from depth electrodes, or computed
from very high time resolution, non-invasive, extracranial recordings of scalp
electric potential differences (EEG: electroencephalogram) and magnetic fields
(MEG: magnetoencephalogram) by means of a tomography such as sLORETA
(standardized low resolution brain electromagnetic tomography). There are two
problems in this case. First, in the usual situation of unknown cortical
geometry, the estimated signal at each brain location is a vector with three
components (i.e. a current density vector), which means that coherence and
phase synchronization must be generalized to pairs of multivariate time series.
Second, the inherent low spatial resolution of the EEG/MEG tomography
introduces artificially high zero-lag coherence and phase synchronization. In
this report, solutions to both problems are presented. Two additional
generalizations are briefly mentioned: (1) conditional coherence and phase
synchronization; and (2) non-stationary time-frequency analysis. Finally, a
non-parametric randomization method for connectivity significance testing is
outlined. The new connectivity measures proposed here can be applied to pairs
of univariate EEG/MEG signals, as is traditional in the published literature.
However, these calculations cannot be interpreted as connectivity, since it is
in general incorrect to associate an extracranial electrode or sensor to the
underlying cortex.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 19:48:30 GMT"
},
{
"version": "v2",
"created": "Wed, 13 Jun 2007 11:35:14 GMT"
},
{
"version": "v3",
"created": "Thu, 12 Jul 2007 12:24:44 GMT"
}
] | 2007-07-12T00:00:00 | [
[
"Pascual-Marqui",
"Roberto D.",
""
]
] |
0706.1777 | Edward C. Moran | Carolin N. Cardamone (Yale), Edward C. Moran (Wesleyan), Laura E. Kay
(Barnard) | "Hidden" Seyfert 2 Galaxies in the Chandra Deep Field North | 36 pages, including 10 figures. Accepted for publication in the
Astronomical Journal | Astron.J.134:1263-1275,2007 | 10.1086/520801 | null | astro-ph | null | We have compared the X-ray--to--optical flux ratios (F_x/F_opt) of absorbed
active galactic nuclei (AGNs) in the Chandra Deep Field North (CDF-N) with
those of nearby, optically classified Seyfert 2 galaxies. The comparison
provides an opportunity to explore the extent to which the local population of
absorbed AGNs can account for the properties of the distant, spectroscopically
ambiguous sources that produce the hard X-ray background. Our nearby sample
consists of 38 objects that well represent the local Seyfert 2 luminosity
function. Integrated UBVRI photometry and broadband X-ray observations are
presented. Using these data, we have simulated the F_x/F_opt ratios that local
Seyfert 2s would exhibit if they were observed in the redshift range 0.2 < z <
1.3 as part of the CDF-N. In the simulations we account for the effects of
redshift on flux measurements in fixed observed-frame bands, and the way the
luminosity function of a given population is sampled in a flux-limited survey
like the CDF-N. Overall, we find excellent agreement between our simulations
and the observed distribution of F_x/F_opt ratios for absorbed AGNs in the
CDF-N. Our analysis has thus failed to reveal any physical differences between
the local population of Seyfert 2s and CDF-N sources with similar X-ray
properties. These results support the hypothesis that the nuclear emission
lines of many distant hard X-ray galaxies are hidden in ground-based spectra
due to a combination of observational effects: signal-to-noise ratio,
wavelength coverage, and dilution by host-galaxy light.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 20:00:04 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Cardamone",
"Carolin N.",
"",
"Yale"
],
[
"Moran",
"Edward C.",
"",
"Wesleyan"
],
[
"Kay",
"Laura E.",
"",
"Barnard"
]
] |
0706.1778 | Sudarshan Ananth | Sudarshan Ananth, Stefan Theisen | KLT relations from the Einstein-Hilbert Lagrangian | 9 pages | Phys.Lett.B652:128-134,2007 | 10.1016/j.physletb.2007.07.003 | AEI-2007-061 | hep-th | null | The Kawai-Lewellen-Tye (KLT) relations derived from string theory tell us
that perturbative gravity amplitudes are the "square" of the corresponding
amplitudes in gauge theory. Starting from the light-cone Lagrangian for pure
gravity we make these relations manifest off-shell, for three- and
four-graviton vertices, at the level of the action.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 17:31:35 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ananth",
"Sudarshan",
""
],
[
"Theisen",
"Stefan",
""
]
] |
0706.1779 | Marcelo J. Reboucas | J. Santos, J. S. Alcaniz, M. J. Reboucas, N. Pires | Lookback time bounds from energy conditions | 7 pages, 3 figures. v2: Minor changes, published in Phys.Rev.D in the
present form | Phys.Rev.D76:043519,2007 | 10.1103/PhysRevD.76.043519 | null | astro-ph gr-qc hep-th | null | In general relativity, the energy conditions are invoked to restrict general
energy-momentum tensors on physical grounds. We show that in the standard
Friedmann-Lemaitre-Robertson-Walker (FLRW) approach to cosmological modeling,
where the energy and matter components of the cosmic fluid are unknown, the
energy conditions provide model-independent bounds on the behavior of the
lookback time of cosmic sources as a function of the redshift for any value of
the spatial curvature. We also confront such bounds with a lookback time sample
which is built from the age estimates of 32 galaxies lying in the interval
$0.11 \lesssim z \lesssim 1.84$ and by assuming the total expanding age of the
Universe to be $13.7 \pm 0.2$ Gyr, as obtained from current cosmic microwave
background experiments. In agreement with previous results, we show that all
energy conditions seem to have been violated at some point of the recent past
of cosmic evolution.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 20:37:51 GMT"
},
{
"version": "v2",
"created": "Thu, 23 Aug 2007 22:21:57 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Santos",
"J.",
""
],
[
"Alcaniz",
"J. S.",
""
],
[
"Reboucas",
"M. J.",
""
],
[
"Pires",
"N.",
""
]
] |
0706.1780 | Marie-France Ango-Obiang | Marie-France Ango-Obiang (SITE, Loria) | Le travail collaboratif dans le cadre d'un projet architectural | null | Dans Innovation et tradition de l'association internationale
Management Strat\'egique (2007) | null | null | cs.HC | null | The analysis of the practices and the tendencies of the users at the time of
the search for information on Internet makes it possible to highlight several
points. The search for information becomes powerful after knowledge of the
typology of the various systems of research. This typology supports the
adoption of a methodology of research which one can characterize by pull
systems, intelligent agents, etc. In addition, the importance of the structure
of the electronic document, correctly elaborated in advance, will support a
higher relevance ratio to find information. In our article, the problems turn
around the study of the behavior of the users in situation of search for
information, as well as the constitution of a pole of documentary resources
within a framework of an architectural project. It is noted that the evolution
of the documentary resources is related to information technologies.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 20:06:38 GMT"
}
] | 2007-06-14T00:00:00 | [
[
"Ango-Obiang",
"Marie-France",
"",
"SITE, Loria"
]
] |
0706.1781 | Marco Ruggieri | R. Anglani, R. Gatto, N. D. Ippolito, G. Nardulli and M. Ruggieri | Superfluid and Pseudo-Goldstone Modes in Three Flavor Crystalline Color
Superconductivity | 10 pages, RevTeX4 class. Section IIIA enlarged, to appear on Phys.
Rev. D | Phys.Rev.D76:054007,2007 | 10.1103/PhysRevD.76.054007 | BARI-TH 567/07 | hep-ph | null | We study the bosonic excitations in the favorite cubic three flavor
crystalline LOFF phases of QCD. We calculate in the Ginzburg-Landau
approximation the masses of the eight pseudo Nambu-Goldstone Bosons (NGB)
present in the low energy theory. We also compute the decay constants of the
massless NGB Goldstones associated to superfluidity as well as those of the
eight pseudo NGB. Differently from the corresponding situation in the
Color-Flavor-Locking phase, we find that meson condensation phases are not
expected in the present scenario.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 14:42:47 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Aug 2007 07:20:21 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Anglani",
"R.",
""
],
[
"Gatto",
"R.",
""
],
[
"Ippolito",
"N. D.",
""
],
[
"Nardulli",
"G.",
""
],
[
"Ruggieri",
"M.",
""
]
] |
0706.1782 | Seth Hornstein | S. D. Hornstein, K. Matthews, A. M. Ghez, J. R. Lu, M. Morris, E. E.
Becklin, M. Rafelski, F. K. Baganoff | A Constant Spectral Index for Sagittarius A* During Infrared/X-ray
Intensity Variations | 11 pages, 7 figures (color), Accepted for publication in ApJ.
Resolution (Fig 1&2) downgraded for astro-ph. For full resolution, see
http://casa.colorado.edu/~hornstei/sgracolor.pdf | Astrophys.J.667:900-910,2007 | 10.1086/520762 | null | astro-ph | null | We report the first time-series of broadband infrared (IR) color measurements
of Sgr A*, the variable emission source associated with the supermassive black
hole at the Galactic Center. Using the laser and natural guide star AO systems
on the Keck II telescope, we imaged Sgr A* in multiple near-infrared broadband
filters with a typical cycle time of ~3 min during 4 observing runs
(2005-2006), two of which were simultaneous with Chandra X-ray measurements. In
spite of the large range of dereddened flux densities for Sgr A* (2-30 mJy),
all of our near-IR measurements are consistent with a constant spectral index
of alpha = -0.6+-0.2. Furthermore, this value is consistent with the spectral
indices observed at X-ray wavelengths during nearly all outbursts; which is
consistent with the synchrotron self-Compton model for the production of the
X-ray emission. During the coordinated observations, one IR outburst occurs <36
min after a possibly associated X-ray outburst, while several similar IR
outbursts show no elevated X-ray emission. A variable X-ray to IR ratio and
constant infrared spectral index challenge the notion that the IR and X-ray
emission are connected to the same electrons. We, therefore, posit that the
population of electrons responsible for both the IR and X-ray emission are
generated by an acceleration mechanism that leaves the bulk of the electron
energy distribution responsible for the IR emission unchanged, but has a
variable high-energy cutoff. Occasionally a tail of electrons >1 GeV is
generated, and it is this high-energy tail that gives rise to the X-ray
outbursts. One possible explanation for this type of variation is from the
turbulence induced by a magnetorotational instability, in which the outer scale
length of the turbulence varies and changes the high-energy cutoff.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 22:02:35 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Hornstein",
"S. D.",
""
],
[
"Matthews",
"K.",
""
],
[
"Ghez",
"A. M.",
""
],
[
"Lu",
"J. R.",
""
],
[
"Morris",
"M.",
""
],
[
"Becklin",
"E. E.",
""
],
[
"Rafelski",
"M.",
""
],
[
"Baganoff",
"F. K.",
""
]
] |
0706.1783 | Stefan Kirchner | Stefan Kirchner and Qimiao Si | Scaling and Enhanced Symmetry at the Quantum Critical Point of the
Sub-Ohmic Bose-Fermi Kondo Model | 4 pages, 3 embedded eps figures; published version | Physical Review Letters 100, 026403 (2008) | 10.1103/PhysRevLett.100.026403 | null | cond-mat.str-el | null | We consider the finite temperature scaling properties of a Kondo-destroying
quantum critical point in the Ising-anisotropic Bose-Fermi Kondo model (BFKM).
A cluster-updating Monte Carlo approach is used, in order to reliably access a
wide temperature range. The scaling function for the two-point spin correlator
is found to have the form dictated by a boundary conformal field theory, even
though the underlying Hamiltonian lacks conformal invariance. Similar
conclusions are reached for all multi-point correlators of the spin-isotropic
BFKM in a dynamical large-N limit. Our results suggest that the quantum
critical local properties of the sub-ohmic BFKM are those of an underlying
boundary conformal field theory.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 20:17:23 GMT"
},
{
"version": "v2",
"created": "Wed, 16 Jan 2008 17:46:49 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Kirchner",
"Stefan",
""
],
[
"Si",
"Qimiao",
""
]
] |
0706.1784 | Rita Pardini | Ciro Ciliberto, Margarida Mendes Lopes and Rita Pardini | Surfaces with K^2<3\chi and finite fundamental group | 18 pages. To appear in Math. Res. Lett | null | null | null | math.AG | null | In this paper we continue the study of algebraic fundamentale group of
minimal surfaces of general type S satisfying K_S^2<3\chi(S). We show that, if
K_S^2= 3\chi(S)-1 and the algebraic fundamental group of S has order 8, then S
is a Campedelli surface.
In view of the results of math.AG/0512483 and math.AG/0605733, this implies
that the fundamental group of a surface with K^2<3\chi that has no irregular
etale cover has order at most 9, and if it has order 8 or 9, then S is a
Campedelli surface.
To obtain this result we establish some classification results for minimal
surfaces of general type such that K^2=3p_g-5 and such that the canonical map
is a birational morphism. We also study rational surfaces with a Z_2^3-action.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 20:27:50 GMT"
}
] | 2007-06-14T00:00:00 | [
[
"Ciliberto",
"Ciro",
""
],
[
"Lopes",
"Margarida Mendes",
""
],
[
"Pardini",
"Rita",
""
]
] |
0706.1785 | Scott N. Walck | Scott N. Walck, David W. Lyons | Maximum stabilizer dimension for nonproduct states | 6 pages | Phys. Rev. A 76, 022303 (2007) | 10.1103/PhysRevA.76.022303 | null | quant-ph | null | Composite quantum states can be classified by how they behave under local
unitary transformations. Each quantum state has a stabilizer subgroup and a
corresponding Lie algebra, the structure of which is a local unitary invariant.
In this paper, we study the structure of the stabilizer subalgebra for n-qubit
pure states, and find its maximum dimension to be n-1 for nonproduct states of
three qubits and higher. The n-qubit Greenberger-Horne-Zeilinger state has a
stabilizer subalgebra that achieves the maximum possible dimension for pure
nonproduct states. The converse, however, is not true: we show examples of pure
4-qubit states that achieve the maximum nonproduct stabilizer dimension, but
have stabilizer subalgebra structures different from that of the n-qubit GHZ
state.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 20:23:31 GMT"
},
{
"version": "v2",
"created": "Fri, 3 Aug 2007 20:57:11 GMT"
}
] | 2008-10-12T00:00:00 | [
[
"Walck",
"Scott N.",
""
],
[
"Lyons",
"David W.",
""
]
] |
0706.1786 | Manfred Salmhofer | Joel Feldman (University of British Columbia) and Manfred Salmhofer
(Universitaet Leipzig) | Singular Fermi Surfaces I. General Power Counting and Higher Dimensional
Cases | 48 pages LaTeX with figures | null | 10.1142/S0129055X08003274 | null | math-ph cond-mat.str-el math.MP | null | We prove regularity properties of the self-energy, to all orders in
perturbation theory, for systems with singular Fermi surfaces which contain Van
Hove points where the gradient of the dispersion relation vanishes. In this
paper, we show for spatial dimensions $d \ge 3$ that despite the Van Hove
singularity, the overlapping loop bounds we proved together with E. Trubowitz
for regular non--nested Fermi surfaces [J. Stat. Phys. 84 (1996) 1209] still
hold, provided that the Fermi surface satisfies a no-nesting condition. This
implies that for a fixed interacting Fermi surface, the self-energy is a
continuously differentiable function of frequency and momentum, so that the
quasiparticle weight and the Fermi velocity remain close to their values in the
noninteracting system to all orders in perturbation theory. In a companion
paper, we treat the more singular two-dimensional case.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 20:24:08 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Feldman",
"Joel",
"",
"University of British Columbia"
],
[
"Salmhofer",
"Manfred",
"",
"Universitaet Leipzig"
]
] |
0706.1787 | Joel N. Bregman | Joel N. Bregman (University of Michigan) | The Search for the Missing Baryons at Low Redshift | To appear in Annual Review of Astronomy and Astrophysics, Vol 45
(Sept 2007) 44 pages, including 11 figures | Ann.Rev.Astron.Astrophys.45:221-259,2007 | 10.1146/annurev.astro.45.051806.110619 | null | astro-ph | null | At low redshift, only about one-tenth of the known baryons lie in galaxies or
the hot gas seen in galaxy clusters and groups. Models posit that these
"missing baryons" are in gaseous form in overdense filaments that connect the
much denser virialized groups and clusters. About 30% are cool (<1E5 K) and are
detected in Ly alpha absorption studies, but about half is predicted to lie in
the 1E5-1E7 K regime. Gas is detected in the 2-5E5 K range through OVI
absorption studies (7% of the baryons) and possibly near 1E5 K from broad Ly
absorption (20% of the baryons). Hotter gas (0.5-2E6 K) is detected at zero
redshift by OVII and OVIII K X-ray absorption, and the OVII line strengths seem
to correlate with the Galactic soft X-ray background, so it is probably
produced by Galactic Halo gas, rather than a Local Group medium. There are no
compelling detections of the intergalactic hot gas (0.5-10E6 K) either in
absorption or emission and these upper limits are consistent with theoretical
models. Claimed X-ray absorption lines are not confirmed, while most of the
claims of soft emission are attributable to artifacts of background subtraction
and field-flattening. The missing baryons should become detectable with
moderate improvements in instrumental sensitivity.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 20:51:13 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Bregman",
"Joel N.",
"",
"University of Michigan"
]
] |
0706.1788 | Manfred Salmhofer | Joel Feldman (University of British Columbia) and Manfred Salmhofer
(Universitaet Leipzig) | Singular Fermi Surfaces II. The Two--Dimensional Case | 68 pages LaTeX with figures | null | 10.1142/S0129055X08003304 | null | math-ph cond-mat.str-el math.MP | null | We consider many--fermion systems with singular Fermi surfaces, which contain
Van Hove points where the gradient of the band function $k \mapsto e(k)$
vanishes. In a previous paper, we have treated the case of spatial dimension $d
\ge 3$. In this paper, we focus on the more singular case $d=2$ and establish
properties of the fermionic self--energy to all orders in perturbation theory.
We show that there is an asymmetry between the spatial and frequency
derivatives of the self--energy. The derivative with respect to the Matsubara
frequency diverges at the Van Hove points, but, surprisingly, the self--energy
is $C^1$ in the spatial momentum to all orders in perturbation theory, provided
the Fermi surface is curved away from the Van Hove points. In a prototypical
example, the second spatial derivative behaves similarly to the first frequency
derivative. We discuss the physical significance of these findings.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 20:30:06 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Feldman",
"Joel",
"",
"University of British Columbia"
],
[
"Salmhofer",
"Manfred",
"",
"Universitaet Leipzig"
]
] |
0706.1789 | Valeri Andreev P. | Valery P. Andreev | B production at the LHC / QCD aspects | Moriond QCD 2007 conference proceedings | null | null | null | hep-ex | null | The LHC provides new opportunities to improve our understanding of the b
quark using high statistics data samples and the 14 TeV center-of-mass energy.
The prospects to measure the cross section for inclusive b production in events
containing jets and at least one muon are presented. Studies of detector
systematic effects and theoretical uncertainties are included. QCD aspects of
the beauty production are discussed.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 20:51:40 GMT"
}
] | 2007-06-14T00:00:00 | [
[
"Andreev",
"Valery P.",
""
]
] |
0706.1790 | Corinne Touati | Arnaud Legrand (INRIA Rh\^one-Alpes / ID-IMAG), Corinne Touati (INRIA
Rh\^one-Alpes / ID-IMAG) | How to measure efficiency? | null | null | null | null | cs.GT | null | In the context of applied game theory in networking environments, a number of
concepts have been proposed to measure both efficiency and optimality of
resource allocations, the most famous certainly being the price of anarchy and
the Jain index. Yet, very few have tried to question these measures and compare
them one to another, in a general framework, which is the aim of the present
article.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 12:25:54 GMT"
},
{
"version": "v2",
"created": "Thu, 14 Jun 2007 16:38:19 GMT"
}
] | 2007-06-14T00:00:00 | [
[
"Legrand",
"Arnaud",
"",
"INRIA Rhône-Alpes / ID-IMAG"
],
[
"Touati",
"Corinne",
"",
"INRIA\n Rhône-Alpes / ID-IMAG"
]
] |
0706.1791 | Andrew Ptak | A. Ptak (1), B.Mobasher (2), A. Hornschemeier (1,3), F. Bauer (4) and
C. Norman (1,2) ((1) Johns Hopkins University, (2) Space Telescope Institute,
(3) NASA/GSFC, (4) Columbia University) | X-ray Luminosity Functions of Normal Galaxies in the GOODS | 36 pages, 36 figures, formatted with emulateapj. Accepted for
publication in ApJ. Higher resolution version available at
http://xassist.pha.jhu.edu/ptak/goods_xlf_emulateapj.pdf | null | null | null | astro-ph | null | We present soft (0.5-2 keV) X-ray luminosity functions (XLFs) in the Great
Observatories Origins Deep Survey (GOODS) fields, derived for galaxies at
z~0.25 and 0.75. SED fitting was used to estimate photometric redshifts and
separate galaxy types, resulting in a sample of 40 early-type galaxies and 46
late-type galaxies. We estimate k-corrections for both the X-ray/optical and
X-ray/NIR flux ratios, which facilitates the separation of AGN from the
normal/starburst galaxies. We fit the XLFs with a power-law model using both
traditional and Markov-Chain Monte Carlo (MCMC) procedures. The XLFs differ
between z<0.5 and z>0.5, at >99% significance levels for early-type, late-type
and all (early and late-type) galaxies.We also fit Schechter and log-normal
models to the XLFs, fitting the low and high redshift XLFs for a given sample
simultaneously assuming only pure luminosity evolution. In the case of
log-normal fits, the results of MCMC fitting of the local FIR luminosity
function were used as priors for the faint and bright-end slopes (similar to
``fixing'' these parameters at the FIR values except here the FIR uncertainty
is included). The best-fit values of the change in log L* with redshift were
dlogL* = 0.23 +/- 0.16 dex (for early-type galaxies) and 0.34 +/- 0.12 dex (for
late-type galaxies), corresponding to (1+z)^1.6 and (1+z)^2.3. These results
were insensitive to whether the Schechter or log-normal function was adopted.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 20:37:45 GMT"
}
] | 2007-06-14T00:00:00 | [
[
"Ptak",
"A.",
""
],
[
"Mobasher",
"B.",
""
],
[
"Hornschemeier",
"A.",
""
],
[
"Bauer",
"F.",
""
],
[
"Norman",
"C.",
""
]
] |
0706.1792 | Caucher Birkar | Caucher Birkar | On existence of log minimal models | null | Compositio Math. 146 (2010) 919-928 | 10.1112/S0010437X09004564 | null | math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this paper, we prove that the log minimal model program in dimension $d-1$
implies the existence of log minimal models for effective lc pairs (eg of
nonnegative Kodaira dimension) in dimension $d$. In fact, we prove that the
same conclusion follows from a weaker assumption, namely, the log minimal model
program with scaling in dimension $d-1$. This enables us to prove that
effective lc pairs in dimension five have log minimal models. We also give new
proofs of the existence of log minimal models for effective lc pairs in
dimension four and the Shokurov reduction theorem. Other applications appear in
a paper of Birkar-Paun.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 21:36:47 GMT"
},
{
"version": "v2",
"created": "Thu, 3 Jul 2008 00:45:11 GMT"
},
{
"version": "v3",
"created": "Thu, 23 Jul 2009 20:53:01 GMT"
}
] | 2019-02-20T00:00:00 | [
[
"Birkar",
"Caucher",
""
]
] |
0706.1793 | C\'esar Seijas | Cesar Seijas | The beta function of gauge theories at two loops in differential
renormalization | PhD Thesis, 137 pages, 20 figures, LaTeX. v2 references added | null | null | null | hep-th | null | This PhD thesis is devoted to show that differential renormalization is a
simple and useful renormalization method that we can use when dealing with
gauge theories. In this work, it is shown how the one-loop results of
Constraint Differential Renormalization can be fruitfully applied when
renormalizing two-loop amplitudes. As an example of this procedure, the
two-loop beta functions of various relevant gauge theories are obtained (QED,
SuperQED, Yang-Mills and N=1 SuperYM) without making use of the Ward
identities, which are mandatory in the standard differential renormalization
procedure. Also, we study how to deal with expressions that have IR and UV
divergences, showing that both are renormalized with independent scales. This
result allow us to give new insight on the origin of the higher order
corrections to the beta function of the N=1 SuperYM theory, as in this case we
have both divergences due to the form of the gauge propagator. This is an
advantage over usual dimensional regularization methods, where both divergences
become mixed.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 22:24:35 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jun 2007 21:03:33 GMT"
}
] | 2007-06-27T00:00:00 | [
[
"Seijas",
"Cesar",
""
]
] |
0706.1794 | Caucher Birkar | Caucher Birkar | Birational geometry | 35 pages | null | null | null | math.AG | null | This article contains the notes of a graduate course on birational geometry
focusing on the minimal model program. Topics covered include singularities,
vanishing, nonvanishing, cone and contraction, base point freeness, finite
generation, flips, termination, minimal models and Mori fibre spaces.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 14:16:48 GMT"
}
] | 2007-06-14T00:00:00 | [
[
"Birkar",
"Caucher",
""
]
] |
0706.1795 | Oisin A. P. Mac Conamhna | Oisin A. P. Mac Conamhna | Inverting geometric transitions: explicit Calabi-Yau metrics for the
Maldacena-Nunez solutions | 1+17 pages, LaTeX; v2, typos corrected; v3, typos corrected, final
version | Phys.Rev.D76:106010,2007 | 10.1103/PhysRevD.76.106010 | Imperial/TP/2007/OC/02 | hep-th | null | Explicit Calabi-Yau metrics are derived that are argued to map to the
Maldacena-Nu\~{n}ez AdS solutions of M-theory and IIB under geometric
transitions. In each case the metrics are singular where a H^2 K\"{a}hler
two-cycle degenerates but are otherwise smooth. They are derived as the most
general Calabi-Yau solutions of an ansatz for the supergravity description of
branes wrapped on K\"{a}hler two-cycles. The ansatz is inspired by re-writing
the AdS solutions, and the structure defined by half their Killing spinors, in
this form. The world-volume theories of fractional branes wrapped at the
singularities of these metrics are proposed as the duals of the AdS solutions.
The existence of supergravity solutions interpolating between the $AdS$ and
Calabi-Yau metrics is conjectured and their boundary conditions briefly
discussed.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 22:14:35 GMT"
},
{
"version": "v2",
"created": "Mon, 6 Aug 2007 12:54:18 GMT"
},
{
"version": "v3",
"created": "Mon, 29 Oct 2007 22:58:33 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mac Conamhna",
"Oisin A. P.",
""
]
] |
0706.1796 | Christophe Royon | C. Royon (for the RP220 Collaboration) | Project to install roman pot detectors at 220 m in ATLAS | Proceedings for the DIS 2007 workshop, Munich, April 2007 | null | null | null | physics.ins-det hep-ex | null | We give a short description of the project to install roman pot detectors at
220 m from the interaction point in ATLAS. This project is dedicated to hard
diffractive measurements at high luminosity.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 22:23:46 GMT"
}
] | 2019-08-14T00:00:00 | [
[
"Royon",
"C.",
"",
"for the RP220 Collaboration"
]
] |
0706.1797 | Marvin D. Girardeau | M.D. Girardeau and A. Minguzzi | Soluble Models of Strongly Interacting Ultracold Gas Mixtures in Tight
Waveguides | Revised to discuss splitting of degenerate ground manifold for large
but finite BB and BF repulsions; accepted by PRL | null | 10.1103/PhysRevLett.99.230402 | null | cond-mat.other | null | A generalized Fermi-Bose mapping method is used to determine the exact ground
states of several models of mixtures of strongly interacting ultracold gases in
tight waveguides, which are generalizations of the Tonks-Girardeau (TG) gas (1D
Bose gas with point hard cores) and fermionic Tonks-Girardeau (FTG) gas (1D
spin-aligned Fermi gas with infinitely strong zero-range attractions). We
detail the case of a Bose-Fermi mixture with TG boson-boson (BB) and
boson-fermion (BF) interactions. Exact results are given for density profiles
in a harmonic trap, single-particle density matrices, momentum distributions,
and density-density correlations. Since the ground state is highly degenerate,
we analyze the splitting of the ground manifold for large but finite BB and BF
repulsions.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 22:24:13 GMT"
},
{
"version": "v2",
"created": "Fri, 19 Oct 2007 18:33:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Girardeau",
"M. D.",
""
],
[
"Minguzzi",
"A.",
""
]
] |
0706.1798 | Christophe Royon | O. Kepka, C. Royon | New QCD fits to HERA data and search for exclusive events at the
Tevatron | Proceedings for the DIS 2007 workshop, Munich, April 2007 | null | null | null | hep-ph | null | We describe new QCD fits to diffractive proton structure functions measured
at HERA, and we use these parton densities to predict the shape of the dijet
mass fraction at the Tevatron and look for the existence of exclusive events in
the dijet channel.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 22:27:42 GMT"
}
] | 2007-06-14T00:00:00 | [
[
"Kepka",
"O.",
""
],
[
"Royon",
"C.",
""
]
] |
0706.1799 | Christophe Royon | C. Royon | BFKL NLL phenomenology of forward jets at HERA and Mueller Navelet jets
at the Tevatron and the LHC | Proceedings for the DIS 2007 workshop, Munich, April 2007 | null | null | null | hep-ph | null | We perform a BFKL-NLL analysis of forward jet production at HERA which leads
to a good description of data over the full kinematical domain. We also predict
the azimuthal angle dependence of Mueller-Navelet jet production at the
Tevatron and the LHC using the BFKL NLL formalism.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 22:35:23 GMT"
}
] | 2007-06-14T00:00:00 | [
[
"Royon",
"C.",
""
]
] |
0706.1800 | Peter McNamara | Peter R. W. McNamara | Necessary Conditions for Schur-Positivity | 12 pages, 4 figures. Fixed typos; final version. To appear in the
Journal of Algebraic Combinatorics | J. Algebraic Combin. 28 (4) (2008) 495-507 | null | null | math.CO | null | In recent years, there has been considerable interest in showing that certain
conditions on skew shapes A and B are sufficient for the difference s_A - s_B
of their skew Schur functions to be Schur-positive. We determine necessary
conditions for the difference to be Schur-positive. Our conditions are
motivated by those of Reiner, Shaw and van Willigenburg that are necessary for
s_A = s_B, and we deduce a strengthening of their result as a special case.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 22:58:57 GMT"
},
{
"version": "v2",
"created": "Thu, 13 Dec 2007 15:59:27 GMT"
},
{
"version": "v3",
"created": "Fri, 21 Dec 2007 18:40:23 GMT"
}
] | 2008-10-02T00:00:00 | [
[
"McNamara",
"Peter R. W.",
""
]
] |
0706.1801 | Elizabeth Fernandez | Elizabeth R. Fernandez and Eiichiro Komatsu | Mass-to-light Ratio of Ly-alpha Emitters: Implications of Ly-alpha
Surveys at Redshifts z=5.7, 6.5, 7, and 8.8 | 15 pages, 4 figures, Accepted to MNRAS. Explanations and references
added in response to referee | AIP Conf.Proc.990:201-203,2008 | 10.1063/1.2905541 | null | astro-ph | null | Using a simple method to interpret the luminosity function of Ly-alpha
emitters, we explore properties of Ly-alpha emitters from 5.7 < z < 8.8 with
various assumptions about metallicity and stellar mass spectra. We constrain a
mass-to-'observed' light ratio, M_h/L_band. For narrow-band surveys, L_band is
simply related to the intrinsic Ly-alpha luminosity with a survival fraction of
Ly-alpha photons, alpha_esc. The mass-to-'bolometric light', M_h/L_bol, can
also be deduced, once the metallicity and stellar mass spectrum are given. The
inferred M_h/L_bol is more sensitive to metallicity than to the mass spectrum.
We find the following constraints on a mass-to-light ratio of Ly-alpha emitters
from 5.7 < z < 7: (M_h/L_bol)(alpha_{esc}epsilon^{1/gamma})^{-1}=21-38, 14-26,
and 9-17 for Z=0, 1/50, and 1 Z_sun, respectively, where epsilon is the 'duty
cycle' of Ly-alpha emitters, and gamma ~ 2 is a local slope of the cumulative
luminosity function. Only weak lower limits are obtained for z=8.8. Therefore,
Ly-alpha emitters are consistent with either starburst galaxies M_h/L_bol ~
0.1-1 with a smaller Ly-alpha survival fraction, alpha_{esc}epsilon^{1/gamma}
~0.01-0.05, or normal populations (M_h/L_bol ~ 10) if a good fraction of
Ly-alpha photons survived, alpha_{esc}epsilon^{1/gamma} ~ 0.5-1. We find no
evidence for the end of reionization in the luminosity functions of Ly-alpha
emitters discovered in the current Ly-alpha surveys, including recent discovery
of one Ly-alpha emitter at z=7. The data are consistent with no evolution of
intrinsic properties of Ly-alpha emitters or neutral fraction in the
intergalactic medium up to z=7. No detection of sources at z=8.8 does not yield
a significant constraint yet. We also show that the lack of detection at z=8.8
does not rule out the high-z galaxies being the origin of the excess NIRB.
| [
{
"version": "v1",
"created": "Tue, 12 Jun 2007 23:12:23 GMT"
},
{
"version": "v2",
"created": "Tue, 16 Oct 2007 21:56:12 GMT"
}
] | 2010-12-13T00:00:00 | [
[
"Fernandez",
"Elizabeth R.",
""
],
[
"Komatsu",
"Eiichiro",
""
]
] |
0706.1802 | Vladimir Mashkevich | Vladimir Mashkevich (CUNY) | Notes on Quantum Field Theory in Curved Spacetime: Problems Relating to
the Concept of Particles and Hamiltonian Formalism | 27 pages, LaTeX 2e. Substantially extended, sections on applications
to black hole and universe added | null | null | null | physics.gen-ph | null | The aim of these notes is to elucidate some aspects of quantum field theory
in curved spacetime, especially those relating to the notion of particles. A
selection of issues relevant to wave-particle duality is given. The case of a
generic curved spacetime is outlined. A Hamiltonian formulation of quantum
field theory in curved spacetime is elaborated for a preferred reference frame
with a separated space metric (a static spacetime and a reductive synchronous
reference frame). Applications: (1) Black hole. (2) The universe; the
cosmological redshift is obtained in the context of quantum field theory.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 00:10:23 GMT"
},
{
"version": "v2",
"created": "Thu, 13 Mar 2008 02:26:14 GMT"
}
] | 2008-03-13T00:00:00 | [
[
"Mashkevich",
"Vladimir",
"",
"CUNY"
]
] |
0706.1803 | Miguel Pruneda J. | J. M. Pruneda, D. Sanchez-Portal, A. Arnau, J. I. Juaristi, Emilio
Artacho | Electronic stopping power in insulators from first principles | null | null | 10.1103/PhysRevLett.99.235501 | null | cond-mat.mtrl-sci | null | Using time-dependent density-functional theory we calculate from first
principles the rate of energy transfer from a moving proton or antiproton to
the electrons of an insulating material, LiF. The behavior of the electronic
stopping power versus projectile velocity displays an effective threshold
velocity of ~0.2 a.u. for the proton, consistent with recent experimental
observations, and also for the antiproton. The calculated proton/antiproton
stopping-power ratio is ~2.4 at velocities slightly above the threshold (v~0.4
a.u.), as compared to the experimental value of 2.1. The projectile energy loss
mechanism is observed to be stationary and extremely local.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 02:14:04 GMT"
},
{
"version": "v2",
"created": "Fri, 15 Jun 2007 17:45:32 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pruneda",
"J. M.",
""
],
[
"Sanchez-Portal",
"D.",
""
],
[
"Arnau",
"A.",
""
],
[
"Juaristi",
"J. I.",
""
],
[
"Artacho",
"Emilio",
""
]
] |
0706.1804 | Heather King | H. King, J.M. Matthews, J.F. Rowe, C.Cameron, R.Kuschnig, D.B.
Guenther, A.F.J. Moffat, S.M. Rucinski, D. Sasselov, G.A.H. Walker, W.W.
Weiss | HD 114839 - An Am star showing both delta Scuti and gamma Dor pulsations
discovered through MOST photometry | null | King, H. et al., 2007, CoAst, 143 | null | null | astro-ph | null | Using MOST (Microvariability and Oscillations of STars) satellite guide star
photometry, we have discovered a metallic A star showing hybrid p- and g-mode
pulsations. HD 114839 was observed nearly continuously for 10 days in March,
2005. We identify frequencies in three groups: the first centered near 2
cycles/day, in the gamma Dor pulsation range, and two others near 8 and 20,
both in the delta Scuti range. This is only the fourth known such hybrid
pulsator, including another MOST discovery (Rowe et al. 2006, this issue).
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 00:36:27 GMT"
},
{
"version": "v2",
"created": "Thu, 14 Jun 2007 21:43:29 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"King",
"H.",
""
],
[
"Matthews",
"J. M.",
""
],
[
"Rowe",
"J. F.",
""
],
[
"Cameron",
"C.",
""
],
[
"Kuschnig",
"R.",
""
],
[
"Guenther",
"D. B.",
""
],
[
"Moffat",
"A. F. J.",
""
],
[
"Rucinski",
"S. M.",
""
],
[
"Sasselov",
"D.",
""
],
[
"Walker",
"G. A. H.",
""
],
[
"Weiss",
"W. W.",
""
]
] |
0706.1805 | Zoltan Zimboras | S. Farkas, Z. Zimboras | The von Neumann entropy asymptotics in multidimensional fermionic
systems | 10 pages | J. Math. Phys. 48, 102110 (2007) | 10.1063/1.2800167 | null | math-ph cond-mat.stat-mech math.MP quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We study the von Neumann entropy asymptotics of pure translation-invariant
quasi-free states of d-dimensional fermionic systems. It is shown that the
entropic area law is violated by all these states: apart from the trivial
cases, the entropy of a cubic subsystem with edge length L cannot grow slower
than L^{d-1}ln L. As for the upper bound of the entropy asymptotics, the
zero-entropy-density property of these pure states is the only limit: it is
proven that arbitrary fast sub-L^d entropy growth is achievable.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 11:10:22 GMT"
},
{
"version": "v2",
"created": "Thu, 5 May 2011 21:10:52 GMT"
}
] | 2011-05-09T00:00:00 | [
[
"Farkas",
"S.",
""
],
[
"Zimboras",
"Z.",
""
]
] |
0706.1806 | Erwin Mi\~na-D\'iaz | Erwin Mi\~na-D\'iaz | On the asymptotic behavior of Faber polynomials for domains with
piecewise analytic boundary | 39 pages, 4 figures | Constructive Approximation. Vol. 29, 3:421-448 (2009). | 10.1007/s00365-008-9033-z | null | math.CA math.CV | null | For a function g(w) analytic and univalent in {w:1<|w|<\infty} with a simple
pole at \infty and a continuous extension to {w:|w|\geq 1}, we consider the
Faber polynomials F_n(z), n=0,1,2,..., associated to g(w) via their generating
function g'(w)/(g(w)-z)=\sum_{n=0}^\infty F_n(z)w^{-(n+1)}. Assuming that g(w)
maps the unit circle T onto a piecewise analytic curve L whose exterior domain
has no outward-pointing cusps, and under an additional assumption concerning
the "Lehman expansion" of g(w) about those points of T mapped onto corners of
L, we obtain asymptotic formulas for F_n(z) that yield fine results on the
location, limiting distribution and accumulation points of the zeros of the
Faber polynomials. The asymptotic formulas are shown to hold uniformly and the
exact rate of decay of the error terms involved is provided.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 00:38:42 GMT"
}
] | 2009-03-19T00:00:00 | [
[
"Miña-Díaz",
"Erwin",
""
]
] |
0706.1807 | Christopher Tuffley | Christopher Tuffley | Generalised knot groups distinguish the square and granny knots (with an
appendix by David Savitt) | 25 pages, 5 figures, to appear in JKTR. v3: example of the target
groups added; slight correction to the construction of the target groups;
references updated; some changes to notation. v2: section 4.2 expanded to
give overview of proof | J. Knot Theory Ramifications 18(8):1129-1157 (2009) | 10.1142/S0218216509007385 | null | math.GT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Given a knot K we may construct a group G_n(K) from the fundamental group of
K by adjoining an nth root of the meridian that commutes with the corresponding
longitude. These "generalised knot groups" were introduced independently by
Wada and Kelly, and contain the fundamental group as a subgroup. The square
knot SK and the granny knot GK are a well known example of a pair of distinct
knots with isomorphic fundamental groups. We show that G_n(SK) and G_n(GK) are
non-isomorphic for all n>1. This confirms a conjecture of Lin and Nelson, and
shows that the isomorphism type of G_n(K), n>1, carries more information about
K than the isomorphism type of the fundamental group. An appendix by David
Savitt contains some results on representations of the trefoil group in
PSL(2,p) that are needed for the proof.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 08:05:50 GMT"
},
{
"version": "v2",
"created": "Wed, 27 Jun 2007 22:05:53 GMT"
},
{
"version": "v3",
"created": "Fri, 27 Jun 2008 02:49:03 GMT"
}
] | 2009-09-14T00:00:00 | [
[
"Tuffley",
"Christopher",
""
]
] |
0706.1808 | Chuanming Zong | Chuanming Zong | Simultaneous packing and covering in the two-dimensional Euclidean plane
II | 17 pages, 6 figures | null | null | null | math.MG math.NT | null | This paper determines the optimal upper bound for the simultaneous packing
and covering constants of the two-dimensional centrally symmetric convex
domains. It solved a problem opening for more than thirty years.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 01:30:14 GMT"
}
] | 2007-06-14T00:00:00 | [
[
"Zong",
"Chuanming",
""
]
] |
0706.1809 | Nicholas Chapman | Nicholas L. Chapman, Shih-Ping Lai, Lee G. Mundy, Neal J. Evans II,
Timothy Y. Brooke, Lucas A. Cieza, William J. Spiesman, Luisa M. Rebull, Karl
R. Stapelfeldt, Alberto Noriega-Crespo, Lauranne Lanz, Lori E. Allen,
Geoffrey A. Blake, Tyler L. Bourke, Paul M. Harvey, Tracy L. Huard, Jes K.
J{\o}rgensen, David W. Koerner, Philip C. Myers, Deborah L. Padgett, Annelia
I. Sargent, Peter Teuben, Ewine F. van Dishoeck, Zahed Wahhaj, and Kaisa E.
Young | The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. IV. Lupus
Observed with MIPS | 15 pages, 17 figures, uses emulateapj.cls. Accepted for publication
in ApJ. A version with high-quality figures can be found at
http://peggysue.as.utexas.edu/SIRTF/ | Astrophys.J.667:288-302,2007 | 10.1086/520790 | null | astro-ph | null | We present maps of 7.78 square degrees of the Lupus molecular cloud complex
at 24, 70, and $160\:\mu$m. They were made with the Spitzer Space Telescope's
Multiband Imaging Photometer for Spitzer (MIPS) instrument as part of the
Spitzer Legacy Program, ``From Molecular Cores to Planet-Forming Disks'' (c2d).
The maps cover three separate regions in Lupus, denoted I, III, and IV. We
discuss the c2d pipeline and how our data processing differs from it. We
compare source counts in the three regions with two other data sets and
predicted star counts from the Wainscoat model. This comparison shows the
contribution from background galaxies in Lupus I. We also create two color
magnitude diagrams using the 2MASS and MIPS data. From these results, we can
identify background galaxies and distinguish them from probable young stellar
objects. The sources in our catalogs are classified based on their spectral
energy distribution (SED) from 2MASS and Spitzer wavelengths to create a sample
of young stellar object candidates. From 2MASS data, we create extinction maps
for each region and note a strong corresponence between the extinction and the
$160\:\mu$m emission. The masses we derived in each Lupus cloud from our
extinction maps are compared to masses estimated from $^{13}$CO and C$^{18}$O
and found to be similar to our extinction masses in some regions, but
significantly different in others. Finally, based on our color-magnitude
diagrams, we selected 12 of our reddest candidate young stellar objects for
individual discussion. Five of the 12 appear to be newly-discovered YSOs.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 01:48:31 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Chapman",
"Nicholas L.",
""
],
[
"Lai",
"Shih-Ping",
""
],
[
"Mundy",
"Lee G.",
""
],
[
"Evans",
"Neal J.",
"II"
],
[
"Brooke",
"Timothy Y.",
""
],
[
"Cieza",
"Lucas A.",
""
],
[
"Spiesman",
"William J.",
""
],
[
"Rebull",
"Luisa M.",
""
],
[
"Stapelfeldt",
"Karl R.",
""
],
[
"Noriega-Crespo",
"Alberto",
""
],
[
"Lanz",
"Lauranne",
""
],
[
"Allen",
"Lori E.",
""
],
[
"Blake",
"Geoffrey A.",
""
],
[
"Bourke",
"Tyler L.",
""
],
[
"Harvey",
"Paul M.",
""
],
[
"Huard",
"Tracy L.",
""
],
[
"Jørgensen",
"Jes K.",
""
],
[
"Koerner",
"David W.",
""
],
[
"Myers",
"Philip C.",
""
],
[
"Padgett",
"Deborah L.",
""
],
[
"Sargent",
"Annelia I.",
""
],
[
"Teuben",
"Peter",
""
],
[
"van Dishoeck",
"Ewine F.",
""
],
[
"Wahhaj",
"Zahed",
""
],
[
"Young",
"Kaisa E.",
""
]
] |
0706.1810 | Sandro Mattarei | Sandro Mattarei | A sufficient condition for a number to be the order of a nonsingular
derivation of a Lie algebra | 10 pages. This version has been revised according to a referee's
suggestions. The additions include a discussion of the (lower) density of the
set N_p, and the results of more extensive machine computations. Note that
the title has also changed. To appear in Israel J. Math | Israel J. Math. 171 (2009), no. 1, 1-14 | 10.1007/s11856-009-0036-7 | null | math.RA math.NT | null | A study of the set N_p of positive integers which occur as orders of
nonsingular derivations of finite-dimensional non-nilpotent Lie algebras of
characteristic p>0 was initiated by Shalev and continued by the present author.
The main goal of this paper is to show the abundance of elements of N_p. Our
main result shows that any divisor n of q-1, where q is a power of p, such that
$n\ge (p-1)^{1/p} (q-1)^{1-1/(2p)}$, belongs to N_p. This extends its special
case for p=2 which was proved in a previous paper by a different method.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 13:49:05 GMT"
},
{
"version": "v2",
"created": "Wed, 17 Oct 2007 16:29:04 GMT"
}
] | 2010-06-28T00:00:00 | [
[
"Mattarei",
"Sandro",
""
]
] |
0706.1811 | Wilton Dias | J.R.D. Lepine, Wilton S. Dias and Yuri Mishurov | Direct determination of the epicycle frequency in the galactic disk, and
the derived rotation velocity V0 | 18 pages, 14 figures, submitted to ApJ | null | null | null | astro-ph | null | We present a method which allows a direct measurement of the epicycle
frequency $\kappa$ in the galactic disk, using the large database on open
clusters completed by our group. The observed velocity vector (amplitude and
direction) of the clusters in the galactic plane is derived from the catalog
data. In the epicycle approximation, this velocity is the sum of the circular
velocity, described by the galactic rotation curve, and of a residual velocity,
which has a direction that rotates with the frequency $\kappa$. If for some
reason the clusters are formed with non-random initial perturbation velocity
direction (measured for instance with respect to the direction of circular
rotation), then a plot of the orientation angle of the residual velocity as a
function of age reveals the epicycle frequency. The data analysis confirms that
this is the case; due to the non-random initial velocities, it is possible to
measure $\kappa$ for different galactic radii. Our analysis considers that the
effect of the arms on the stellar orbits is small (the Galactic potential is
mainly axis-symmetric); in this sense our results do not depend on any specific
model of the spiral structure, like the existence of a given number of spiral
arms, or on a particular choice of the radius of corotation. The values of
$\kappa$ provide constraints on the rotation velocity of the disk and on its
minimum beyond the solar radius; in particular, $V_0$ is found to be 226 $\pm$
15 kms$^{-1}$ even if the short scale (R$_0$ = 7.5 kpc) of the galaxy is
adopted. The mesured $\kappa$ at the solar radius is 42$\pm$4
kms$^{-1}$kpc$^{-1}$.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 02:12:13 GMT"
}
] | 2007-06-14T00:00:00 | [
[
"Lepine",
"J. R. D.",
""
],
[
"Dias",
"Wilton S.",
""
],
[
"Mishurov",
"Yuri",
""
]
] |
0706.1812 | Praveen Chandra Srivastava | P.C.Srivastava and I.Mehrotra | Shell model study of neutron rich oxygen isotopes | 19 pages,12 figures,Presented at INPC-2007,June 3-8,Tokyo,Japan | null | null | null | nucl-th | null | Shell model calculations for low lying energy states of neutron rich oxygen
isotopes 19O, 20O, 21O, 22O, 23O, 24O, 25O, 26O have been performed using
OXBASH code. The configuration space consists of 0d5/2, 1s1/2, 0d3/2 orbital
for neutrons outside the 16O core. Different interactions namely, Wildenthal,
Preedom-Wildenthal, Wildenthal-Mcgrory and renormalized Kuo and Brown, which
are either empirical or realistic in nature have been used in the calculation,
The calculated energy spectrum are in good agreement with the experimental data
wherever available for the empirical interactions and the correct ordering of
levels is reproduced. The levels obtained from realistic interactions, though
have a small rms deviation, do not reproduce the correct ordering in some of
the cases. In the case of 21O, realistic interactions predict a much too
compressed 1/2+ state at energy 0.157 MeV compared to the experimental value of
1.218 MeV. For even isotopes the variation of the energy of the first 2+exited
state has been studied as a function of neutron number N. A sharp rise in the
value is observed at N=16 for both empirical and realistic interactions and
only at N=14 for empirical interactions. Significantly higher energy of first
2+ exited state compared to the value in the neighboring even-even nuclei is
considered as a signature for magic nuclei at N=14 and N=16.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 02:10:59 GMT"
}
] | 2007-06-14T00:00:00 | [
[
"Srivastava",
"P. C.",
""
],
[
"Mehrotra",
"I.",
""
]
] |
0706.1813 | Satoshi Uchiyama | Luigi Accardi and Satoshi Uchiyama | Uniqueness of the EPR--chemeleon model | 25pages | null | null | null | quant-ph | null | A classical deterministic, reversible dynamical systems, reproducing the
Einstein--Podolsky--Rosen (EPR) correlations in full respect of causality and
locality and without the introduction of any ad hoc selection procedure, was
constructed in the paper [AIR02].
In the present paper we prove that the above mentioned model is unique (see
Theorem (2) in the sense that any local causal probability measure which
reproduces the EPR correlations must coincide, under natural and generic
assumptions, with the one constructed in [AIR02].
[AIR02] L. Accardi, K. Imafuku and M. Regoli, "ON THE EPR--CHAMELEON
EXPERIMENT", Infinite Dimensional Analysis, Quantum Probability and Related
Topics, vol. 5 (2002) 1--20.
| [
{
"version": "v1",
"created": "Wed, 13 Jun 2007 02:43:41 GMT"
}
] | 2007-06-14T00:00:00 | [
[
"Accardi",
"Luigi",
""
],
[
"Uchiyama",
"Satoshi",
""
]
] |
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